TY - JOUR A1 - Sternbaek, L. A1 - Kimani, Martha Wamaitha A1 - Gawlitza, Kornelia A1 - Rurack, Knut A1 - Janicke, B. A1 - Alm, K. A1 - Gjörloff-Wingren, A. A1 - Eriksson, H. T1 - Molecularly Imprinted Polymers Exhibit Low Cytotoxic and Inflammatory Properties in Macrophages In Vitro N2 - Molecularly imprinted polymers (MIPs) against sialic acid (SA) have been developed as a detection tool to target cancer cells. Before proceeding to in vivo studies, a better knowledge of the overall effects of MIPs on the innate immune system is needed. The aim of this study thus was to exemplarily assess whether SA-MIPs lead to inflammatory and/or cytotoxic responses when administered to phagocytosing cells in the innate immune system. The response of monocytic/macrophage cell lines to two different reference particles, Alhydrogel and PLGA, was compared to their response to SA-MIPs. In vitro culture showed a cellular association of SA-MIPs and Alhydrogel, as analyzed by flow cytometry. The reference particle Alhydrogel induced secretion of IL-1b from the monocytic cell line THP-1, whereas almost no secretion was provoked for SA-MIPs. A reduced number of both THP-1 and RAW 264.7 cells were observed after incubation with SA-MIPs and this was not caused by cytotoxicity. Digital holographic cytometry showed that SA-MIP treatment affected cell division, with much fewer cells dividing. Thus, the reduced number of cells after SA-MIP treatment was not linked to SA-MIPs cytotoxicity. In conclusion, SA-MIPs have a low degree of inflammatory properties, are not cytotoxic, and can be applicable for future in vivo studies. KW - Molecularly imprinted polymers KW - Digital holographic cytometry KW - Cytotoxicity KW - Proinflammatory cytokines PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552250 DO - https://doi.org/10.3390/app12126091 SN - 2076-3417 VL - 12 IS - 12 SP - 1 EP - 16 PB - MDPI CY - Basel AN - OPUS4-55225 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Garrido, E. A1 - Hernández-Sigüenza, G. A1 - Climent, Estela A1 - Marcos, M. D. A1 - Rurack, Knut A1 - Gaviña, P. A1 - Parra, M. A1 - Sancenón, F. A1 - Martí-Centelles, V. A1 - Martínez-Máñez, R. T1 - Strip-based lateral flow-type indicator displacement assay for γ-hydroxybutyric acid (GHB) detection in beverages N2 - The use of gamma-hydroxybutyric acid (GHB) in drug-facilitated sexual assault has increased due to its availability and high solubility in aqueous solutions and alcoholic beverages, necessitating the development of rapid methods for GHB detection. In this respect, portable testing methods for use in the field, based on lateral flow assays (LFAs) and capable of detecting trace concentrations of target analytes, are particularly attractive and hold enormous potential for the detection of illicit drugs. Using this strategy, here we report a rapid, low cost, easy-to-handle strip-based LFA for GHB analysis employing a smartphone for fluorescence readout. At molecular signalling level, the ensemble is based on a Cu2+ complex with a tetradentate ligand and the fluorescent dye coumarin 343, which indicate GHB through an indicator displacement assay (IDA) in aqueous solution. When incorporated in a LFA-based strip test this system shows a detection limit as low as 0.03 μM for GHB in MES buffer solution and is able to detect GHB at concentrations of 0.1 μM in soft drinks and alcoholic beverages in only 1 min. KW - Indicator displacement assay KW - Gamma-hydroxybutyric acid KW - Lateral flow assay KW - Test strip KW - Fluorescent dyes KW - Smartphone readout PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564631 DO - https://doi.org/10.1016/j.snb.2022.133043 SN - 0925-4005 VL - 377 SP - 1 EP - 7 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-56463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hülagü, Deniz A1 - Tobias, Charlie A1 - Gojani, Ardian B. A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan A1 - Hülagü, Deniz T1 - Towards automated scanning electron microscopy image analysis of core-shell microparticles for quasi-3D determination of the surface roughness N2 - Core-shell (CS) particles have been increasingly used for a wide range of applications due to their unique properties by merging individual characteristics of the core and the shell materials. The functionality of the designed particles is strongly influenced by their surface roughness. Quantitative evaluation of the roughness of CS microparticles is, however, a challenging task for Scanning Electron Microscopy (SEM). The SEM images contain two-dimensional (2D) information providing contour roughness data only from the projection of the particle in the horizontal plane. This study presents a practical procedure to achieve more information by tilting the sample holder, hence allowing images of different areas of a single particle to be recorded at different orientations under the same view angle. From the analysis of these images, quasi three-dimensional (3D) information is obtained. Three types of home-made particles were investigated: i) bare polystyrene (PS) particles, ii) PS particles decorated with a first magnetic iron oxide (Fe3O4) nanoparticle shell forming CS microbeads, iii) PS/Fe3O4 particles closed with a second silica (SiO2) shell forming core-shell-shell (CSS) microbeads. A series images of a single particle were taken with stepwise tilted sample holder up to 10° by an SEM with high-resolution and surface sensitive SE-InLens® mode. A reliable analysis tool has been developed by a script in Python to analyze SEM images automatically and to evaluate profile roughness quantitatively, for individual core-shell microparticles. Image analysis consists of segmentation of the images, identifying contour and the centre of the particle, and extracting the root mean squared roughness value (RMS-RQ) of the contour profile from the particle projection within a few seconds. The variation in roughness from batch-to-batch was determined with the purpose to set the method as a routine quality check procedure. Flow cytometry measurements provided complementary data. Measurement uncertainties associated to various particle orientations were also estimated. T2 - ICASS 5th International Conference on Applied Surface Science CY - Palma, Mallorca, Spain DA - 25.04.2022 KW - Core-shell particles KW - Image analysis KW - Roughness KW - Scanning electron microscopy PY - 2022 AN - OPUS4-54774 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tobias, Charlie A1 - Rurack, Knut T1 - Design and Application of Polymer-core/ Silica-shell Particles as Promising Tools for Multiplexed Assays N2 - The simultaneous detection of different analytes has gained increasing importance in recent years, especially in the fields of medical diagnostics and environmental analysis. Multiplex assays allow for a range of biomarkers or pollutants to be rapidly and simultaneously measured. Particularly suitable formats for multiplexing are bead-based assays. The beads employed need to fulfil size and density requirements, important for instance for flow cytometry, and shall exhibit a high modularity to be facilely adapted to various kinds of analytes and detection systems. Core/shell particles are ideally suited in this sense because of their modularity in design and adaptability for various (bio)analytical assays. Here, polystyrene particles coated with different kinds of shells are presented, possessing features that are useful for a multitude of assay formats. The particles in focus were coated with mesoporous and non-porous silica shells, with the possibility to introduce magnetic features to facilitate easier handling dependent on the assay format (e.g., in microfluidics). With high throughput analyses in mind, cytometric model assays were developed. Different factors such as pH or mediator salt used during shell preparation were evaluated with shell inspection by electron microscopy (SEM/TEM/EDX) being key to architectural control of the monodisperse particles. The optimized core/shell particles can be functionalized with capture biomolecules for toxins, viruses, or drugs to demonstrate particle performance. Showing how tailoring of the shell’s surface area controls sensitivity and dynamic range of the assay, an antibody-based assay for the detection of mycotoxins and a multiplex assay for the determination of DNA from different human papilloma virus (HPV) lines were developed. T2 - ICASS 2022 CY - Palma, Mallorca, Spain DA - 25.04.2022 KW - Core–shell particles KW - Multiplexing KW - Surface area control KW - Cytometry PY - 2022 AN - OPUS4-54752 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jiang, Shan A1 - Wang, T. A1 - Behren, S. A1 - Westerlind, U. A1 - Gawlitza, Kornelia A1 - Persson, J. L. A1 - Rurack, Knut T1 - Sialyl-Tn Antigen-Imprinted Dual Fluorescent Core–Shell Nanoparticles for Ratiometric Sialyl-Tn Antigen Detection and Dual-Color Labeling of Cancer Cells N2 - Sialyl-Tn (STn or sialyl-Thomsen-nouveau) is a carbohydrate antigen expressed by more than 80% of human carcinomas. We here report a strategy for ratiometric STn detection and dual-color cancer cell labeling, particularly, by molecularly imprinted polymers (MIPs). Imprinting was based on spectroscopic studies of a urea-containing green-fluorescent monomer 1 and STn-Thr-Na (sodium salt of Neu5Acα2-6GalNAcα-O-Thr). A few-nanometer-thin green-fluorescent polymer shell, in which STn-Thr-Na was imprinted with 1, other comonomers, and a cross-linker, was synthesized from the surface of red-emissive carbon nanodot (R-CND)-doped silica nanoparticles, resulting in dual fluorescent STn-MIPs. Dual-color labeling of cancer cells was achieved since both red and green emissions were detected in two separate channels of the microscope and an improved accuracy was obtained in comparison with single-signal MIPs. The flow cytometric cell analysis showed that the binding of STn-MIPs was significantly higher (p < 0.001) than that of non-imprinted polymer (NIP) control particles within the same cell line, allowing to distinguish populations. Based on the modularity of the luminescent core–fluorescent MIP shell architecture, the concept can be transferred in a straightforward manner to other target analytes. KW - Cancer KW - Core−shell particles KW - Dual-color labeling glycan KW - Molecular imprinting PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563106 DO - https://doi.org/10.1021/acsanm.2c03252 SP - 1 EP - 14 PB - ACS Publications AN - OPUS4-56310 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gawlitza, Kornelia A1 - Kimani, Martha A1 - Kislenko, Evgeniia A1 - Rurack, Knut T1 - Fluorescent molecularly imprinted polymer particles for direct detection of glyphosate in organic solvents and water N2 - Glyphosate (GPS) is the most widely used pesticide in the world whose use increased dramatically after the introduction of genetically modified crops engineered to resist its herbicidal action during application. In recent years, there have been growing concerns over its toxicity following its classification by the International Agency for Research on Cancer (IARC) as a probable carcinogen as well as reports of its ecotoxicological effects. This resulted in increased efforts to develop quick and sensitive detection methods. In this work, molecular imprinting was combined with direct fluorescence detection of GPS by improving its solubility in organic solvents using tetrabutylammonium (TBA+) and tetrahexylammonium (THA+) as counterions. To achieve fluorescence detection, a fluorescent crosslinker containing urea binding motifs was used as a probe for GPS-TBA and GPS-THA salts in chloroform, generating stable complexes through hydrogen bond formation. The GPS/fluorescent dye complexes were imprinted into 2–3 nm molecularly imprinted polymer (MIP) shells on the surface of sub-micron silica particles. Thus, the MIP binding behavior could be easily evaluated by fluorescence titrations in suspension to monitor the spectral changes upon addition of the GPS analytes. While MIPs prepared with GPS-TBA and GPS-THA both displayed satisfactory imprinting following titration with the corresponding analytes in chloroform, GPS-THA MIPs displayed better selectivity against competing molecules. Moreover, the THA+ counterion was found to be a more powerful phase transfer agent than TBA+, enabling the direct fluorescence detection and quantification of GPS in water in a biphasic assay. A limit of detection of 1.45 µM and a linear range of 5–55 µM, which matches well with WHO guidelines for the acceptable daily intake of GPS in water (5.32 µM), have been obtained. The assay can be further optimized to allow miniaturization into microfluidic devices and shows potential for on-field applications by untrained personnel. T2 - 36th European Colloid & Interface Society Conference CY - Chania, Greece DA - 04.09.2022 KW - Glyphosate KW - Molecular Imprinting KW - Core-Shell Particles KW - Fluorescent Urea Receptors PY - 2022 AN - OPUS4-56311 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pérez-Padilla, Victor A1 - Burnage, Samual A1 - Valderrey, Virginia A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Fluorescence detection of perfluorocarboxylic acids with core-shell particles N2 - Perfluorocarboxylic acids (PFCAs) are a family of compounds that consist of a fully perfluorinated carbon backbone and a carboxylic acid moiety1. PFCAs have been classified as substances of very high concern by REACH regulations due to their persistence in the environment, non biodegradability and toxicological effects2. Thus, there is significant interest in detecting PFCAs in ground, waste, surface and drinking water. Fluorescence detection is a portable, easy-to-operate and cost-effective alternative, enabling the onsite detection of these analytes e.g., with miniaturized fluidic sensors. Here, a guanidine benzoxadiazole (BD) dye covalently attached to a polymerizable methacrylate unit was developed for the integration of the dye into polymers and on surfaces. The response behavior of the dye toward PFCAs was assessed in monophasic (EtOAc) and biphasic (EtOAc-H2O) solvent systems, the biphasic system being advantageous for the extraction of the hydrophobic organic acids from the aqueous phase. The BD dye was integrated into sensory silica core-polymer shell particles for the sensing of PFCAs directly in aqueous media. Submicron SiO2 particles were functionalized with 3 (trimethoxysilyl)propyl methacrylate followed by radical polymerization with the BD dye and ethylene glycol dimethacrylate. TEM images showed a homogeneous polymer shell with a thickness of 75±2 nm. By incorporating the BD dye into core-shell particles, lower limits of detection (1.52 µM for perfluorooctanoic acid, PFOA) were achieved if compared to the use of the neat BD dye in a biphasic assay (17.3 µM for PFOA), and excellent discrimination against inorganic acids thanks to the hydrophobic polymer shell. The particle sensory platform has proven to be an alternative for the sensing of PFCAs directly in water. T2 - 5th International Conference on Applied Surface Science (ICASS) 2022 CY - Palma de Mallorca, Spain DA - 25.04.2022 KW - PFOA KW - Emerging pollutants KW - Polymer nanolayers KW - Fluorescence detection KW - Guanidine benzoxadiazole KW - Core-shell particles PY - 2022 AN - OPUS4-56513 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pérez-Padilla, Victor A1 - Kimani, Martha Wamaitha A1 - Valderrey, Virginia A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Direct detection of glyphosate in water with fluorescent molecularly imprinted polymer particles N2 - Analysis of environmental contaminants such as pesticides is increasing in importance due to frequent detection of residues in water reserves and food stuff, as well as lowering of maximum residue levels (MRLs). Molecularly imprinted polymers (MIPs) have been developed for preconcentration of these analytes prior to analysis by chromatographic techniques [1]. MIPs are prepared by polymerization of monomers in a matrix containing the analyte, followed by extraction of the analyte to obtain binding sites that are complementary to the analyte of interest. Recently, our group developed MIPs containing fluorescent reporter molecules that can be used for direct detection and quantification of 2,4-D in contaminated water. Core/shell MIP particles were employed, consisting of sub-micron silica nanoparticles coated with a MIP shell containing a fluorescent reporter whose signal was enhanced upon binding with 2,4-D in water. A limit of detection of 20 nM was attained [2]. We present here a comparable system, composed of fluorescent core-shell MIPs for the direct analysis of pesticides in environmental samples. T2 - UK-Poland-Ukraine Bioinspired Materials Conference CY - Online meeting DA - 29.11.2022 KW - Core-Shell Particles KW - Fluorescent Probes KW - Molecularly Imprinted Polymers KW - Glyphosate KW - Guanidinium Receptors PY - 2022 AN - OPUS4-56514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Valderrey, Virginia A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Thiourea- and Amino-Substituted Benzoxadiazole Dyes with Large Stokes Shifts as Red-Emitting Probe Monomers for Imprinted Polymer Layers Targeting Carboxylate-Containing Antibiotics N2 - Bifunctional fluorescent molecular oxoanion probes based on the benzoxadiazole (BD) chromophore are described which integrate a thiourea binding motif and a polymerizable 2-aminoethyl methacrylate unit in the 4,7-positions of the BD core. Concerted charge transfer in this electron donor-acceptor-donor architecture endows the dyes with strongly Stokes shifted (up to >250 nm) absorption and fluorescence. Binding of electron-rich carboxylate guests at the thiourea receptor leads to further analyte-induced red-shifts of the emission, shifting the fluorescence maximum of the complexes to ≥700 nm. Association constants for acetate are ranging from 1–5×105 M−1 in acetonitrile. Integration of one of the fluorescent probes through its polymerizable moiety into molecularly imprinted polymers (MIPs) grafted from the surface of submicron silica cores yielded fluorescent MIP-coated particle probes for the selective detection of antibiotics containing aliphatic carboxylate groups such as enoxacin (ENOX) at micromolar concentrations in highly polar solvents like acetonitrile. KW - Molecular imprinting KW - Anion recognition KW - Antibiotics KW - Benzoxadiazole dyes KW - Charge transfer KW - Fluorescence PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545027 DO - https://doi.org/10.1002/chem.202104525 SN - 1521-3765 SP - 1 EP - 9 PB - Wiley-VCH AN - OPUS4-54502 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beyer, S. A1 - Kimani, Martha Wamaitha A1 - Zhang, Y. A1 - Verhassel, A. A1 - Sternbæk, L. A1 - Wang, T. A1 - Persson, J. L. A1 - Härkönen, P. A1 - Johansson, E. A1 - Caraballo, R. A1 - Elofsson, M. A1 - Gawlitza, Kornelia A1 - Rurack, Knut A1 - Ohlsson, L. A1 - El-Schich, Z. A1 - Gjörloff Wingren, A. A1 - Stollenwerk, M. M. T1 - Fluorescent Molecularly Imprinted Polymer Layers against Sialic Acid on Silica-coated Polystyrene Cores - Assessment of the Binding Behavior to Cancer Cells N2 - Sialic acid (SA) is a monosaccharide usually linked to the terminus of glycan chains on the cell surface. It plays a crucial role in many biological processes, and hypersialylation is a common feature in cancer. Lectins are widely used to analyze the cell surface expression of SA. However, these protein molecules are usually expensive and easily denatured, which calls for the development of alternative glycan-specific receptors and cell imaging technologies. In this study, SA-imprinted fluorescent core-shell molecularly imprinted polymer particles (SA-MIPs) were employed to recognize SA on the cell surface of cancer cell lines. The SA-MIPs improved suspensibility and scattering properties compared with previously used core-shell SA-MIPs. Although SA-imprinting was performed using SA without preference for the alpha-2,3- and alpha-2,6-SA forms, we screened the cancer cell lines analyzed using the lectins Maackia Amurensis Lectin I (MAL I, alpha-2,3-SA) and Sambucus Nigra Lectin (SNA, alpha-2,6-SA). Our results show that the selected cancer cell lines in this study presented a varied binding behavior with the SA-MIPs. The binding pattern of the lectins was also demonstrated. Moreover, two different pentavalent SA conjugates were used to inhibit the binding of the SA-MIPs to breast, skin, and lung cancer cell lines, demonstrating the specificity of the SA-MIPs in both flow cytometry and confocal fluorescence microscopy. We concluded that the synthesized SA-MIPs might be a powerful future tool in the diagnostic analysis of various cancer cells. KW - Cancer KW - Imprinting KW - Molecularly imprinted polymers KW - SA conjugates KW - Sialic acid PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546625 DO - https://doi.org/110.3390/cancers14081875 SN - 2072-6694 VL - 14 IS - 8 PB - MDPI CY - Basel AN - OPUS4-54662 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Giuseppe, Pignatelli A1 - Anne, Strasse A1 - Gumenyuk, Andrey A1 - Gornushkin, Igor B. T1 - Online monitoring of 3D printing of steel via optical emission spectroscopy N2 - Additive manufacturing by laser metal deposition (LMD) requires continuous online monitoring to ensure quality of printed parts. Optical emission spectroscopy (OES) is proposed for the online detection of printing defects by monitoring minute variations in the temperature of a printed spot during laser scan. A two-lens optical system is attached to a moving laser head and focused on a molten pool created on a substrate during LMD. The light emitted by the pool is collected by an ultraviolet–visible (UV–vis) spectrometer and processed. Two metrics are used to monitor variations in the surface temperature: the spectrally integrated emission intensity and correlation coefficient. The variations in the temperature are introduced by artificial defects, shallow grooves, and holes of various widths and diameters carved on a substrate surface. The metrics show sufficient sensitivity for revealing the surface defects, except for the smallest holes with an under-millimeter diameter. Additionally, numeric simulations are carried out for the detection of emission in the UV–vis and near-infrared (NIR) spectral ranges at various surface temperatures. It is concluded that both the metrics perform better in the NIR range. In general, this work demonstrates that spectrally resolved OES suits well for monitoring surface defects during 3D metal printing. KW - Process control KW - Additive manufacturing KW - Laser metal deposition KW - Optical emission spectroscopy KW - Optical sensor PY - 2022 DO - https://doi.org/10.1515/mt-2021-2082 VL - 64 IS - 1 SP - 24 EP - 32 PB - De Gruyter AN - OPUS4-54413 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kimani, Martha Wamaitha A1 - Pérez-Padilla, Victor A1 - Valderrey, Virginia A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Red-Emitting Polymerizable Guanidinium Dyes as Fluorescent Probes in Molecularly Imprinted Polymers for Glyphosate Detection N2 - The development of methodologies to sense glyphosate has gained momentum due to its toxicological and ecotoxicological effects. In this work, a red-emitting and polymerizable guanidinium benzoxadiazole probe was developed for the fluorescence detection of glyphosate. The interaction of the fluorescent probe and the tetrabutylammonium salt of glyphosate was studied via UV/vis absorption and fluorescence spectroscopy in chloroform and acetonitrile. The selective recognition of glyphosate was achieved by preparing molecularly imprinted polymers, able to discriminate against other common herbicides such as 2,4-dichlorophenoxyacetic acid (2,4-D) and 3,6-dichloro-2-methoxybenzoic acid (dicamba), as thin layers on submicron silica particles. The limits of detection of 4.8 µM and 0.6 µM were obtained for the sensing of glyphosate in chloroform and acetonitrile, respectively. The reported system shows promise for future application in the sensing of glyphosate through further optimization of the dye and the implementation of a biphasic assay with water/organic solvent mixtures for sensing in aqueous environmental samples. KW - Glyphosate KW - Guanidinium receptors KW - Fluorescent probes KW - Molecularly imprinted polymers KW - Core-shell particles PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544441 DO - https://doi.org/10.3390/chemosensors10030099 SN - 2227-9040 VL - 10 IS - 3 SP - 1 EP - 20 PB - MDPI CY - Basel AN - OPUS4-54444 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hülagü, Deniz A1 - Tobias, Charlie A1 - Climent Terol, Estela A1 - Gojani, Ardian A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan T1 - Generalized Analysis Approach of the Profile Roughness by Electron Microscopy with the Example of Hierarchically Grown Polystyrene–Iron Oxide–Silica Core–Shell–Shell Particles N2 - The roughness as a property of core–shell (CS) microparticles plays a key role in their functionality. Quantitative evaluation of the roughness of CS microparticles is, however, a challenging task with approaches using electron microscopy images being scarce and showing pronounced differences in terms of methodology and results. This work presents a generalized method for the reliable roughness determination of nonplanar specimens such as CS particles from electron microscopic images, the method being robust and reproducible with a high accuracy. It involves a self-written software package (Python) that analyzes the recorded images, extracts corresponding data, and calculates the roughness based on the deviation of the identified contour. Images of single particles are taken by a dual mode scanning electron microscopy (SEM) setup which permits imaging of the same field-of-view of the sample with high resolution and surface sensitive in SE InLens mode as well as in transmission mode (TSEM). Herein, a new type of polystyrene core–iron oxide shell–silica shell particles is developed to serve as a set of lower micrometer-sized study objects with different surface roughness; the analysis of their images by the semiautomatic workflow is demonstrating that the particles’ profile roughness can be quantitatively obtained. KW - Core–shell particles KW - Image analysis KW - Nanoparticles KW - Roughness KW - SEM KW - transmission mode PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542576 DO - https://doi.org/10.1002/adem.202101344 SP - 1 EP - 9 PB - Wiley-VCH AN - OPUS4-54257 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hudson, A.D. A1 - Jamieson, O. A1 - Crapnell, R.D. A1 - Rurack, Knut A1 - Soares, T.C.C. A1 - Mecozzi, F. A1 - Laude, A. A1 - Gruber, J. A1 - Novakovic, K. A1 - Peeters, M. T1 - Dual detection of nafcillin using a molecularly imprinted polymer-based platform coupled to thermal and fluorescence read-out N2 - Reported here is the production of molecularly imprinted polymer (MIP) films, integrating a fluorescent moiety that serves as both an element for template interaction and signalling, for the thermal and optical detection of the beta-lactam antibiotic nafcillin. Fluorescein methacrylate (FluMa) was synthesized and introduced during the molecular imprinting process as the sole monomer and in a 1 : 1 mixture with methacrylic acid (MAA), allowing to draw first conclusions on the MIP formation potential of such a rather large and rigid monomer. At first, MIP microparticles containing FluMa were prepared by free radical polymerisation. Optical batch rebinding experiments revealed that FluMa can act as a functional monomer for selective detection of nafcillin; however, the addition of MAA as co-monomer significantly improved performance. Subsequently, thin MIP films containing FluMa were deposited onto functionalised glass slides and the influence of porogen, drying time, and monomer composition was studied. These MIP-functionalised glass electrodes were mounted into a customised 3D-printed flow cell, where changes in the liquid were either evaluated with a thermal device or using fluorescence bright field microscopy. Thermal analysis demonstrated that multiple MIP layers enhanced sensor specificity, with detection in the environmentally relevant range. The fluorescence bright field microscope investigations validated these results, showing an increase in the fluorescence intensity upon exposure of the MIP-functionalised glass slides to nafcillin solutions. These are promising results for developing a portable sensor device that can be deployed for antibiotics outside of a dedicated laboratory environment, especially if sensor design and fluorophore architecture are optimised. KW - Molecularly Imprinted Polymers KW - Fluorescence KW - Antibiotics KW - Heat-transfer Measurements KW - Thin films PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540044 DO - https://doi.org/10.1039/D1MA00192B VL - 2 IS - 15 SP - 5105 EP - 5115 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-54004 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gojani, Ardian T1 - Motion of an ensemble of magnetic microbeads in a microfluidic system N2 - This study describes the motion of magnetizable particles of spherical shape with radius at most of 1 μm, also referred to as microbeads, immersed in a liquid under laminar flow conditions in a microfluidic channel. An external magnetic field is applied in part of the system such that it permeates the channel and is characterized by a spatially varying magnetic field, i.e., the gradient of the magnetic field is nonzero. The beads are superparamagnetic; hence they can reach high level of magnetization in the presence of a magnetic field, and this magnetization disappears when the field is zero. Therein lies the attractiveness of these microbeads and the potential for applications because their motion can be controlled using an external magnetic field. The motion is governed by several factors, including the magnetic force acting on microbeads (particles), the drag force due to viscosity, the interaction between particles and the fluid, as well as the interaction between particles themselves. For a single particle case, the trajectory of the motion is determined by balancing the drag and magnetic forces acting on the particle, a calculation that in general requires numerical integration. For a system consisting of an ensemble of interacting particles, several regimes of motion dominated by one of the factors are identified. Of particular interest are the systems dominated by the large number of particles in the ensemble, i.e., high particle concentration, in which cases the wake influences the flow downstream. This effect is qualitatively investigated by considering the Navier-Stokes equation with and without the magnetic force contribution. T2 - 1st NIP Conference National Institute of Physics (IKF), the Albanian Academy of Sciences CY - Tirana, Albania DA - 10.02.2022 KW - MamaLoCA KW - Microfluidics KW - Magnetophoresis PY - 2022 AN - OPUS4-54366 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Climent Terol, Estela A1 - Rurack, Knut T1 - Streifenschnelltest mit ppt-Empfindlichkeit durch Kombination von Elektrochemilumineszenz-Detektion mit Aptamer-gesteuerter Indikatorfreisetzung aus mesoporösen Nanopartikeln N2 - Die Kombination aus elektrogenerierter Chemilumineszenz (ECL) und Aptamer-gesteuerter Indikatorfreisetzung (gAID) aus magnetischen mesoporösen Silica-Nanopartikeln, die in mit Poly(ethylenglycol) und N-(3-Triethoxysilylpropyl) diethanolamin funktionalisiertes Glasfaserpapier eingebettet sind, ermöglichte die Entwicklung eines Schnelltests, mit dem sich Penicillin direkt in verdünnter Milch bis auf 50 +/- 9 ppt in <5 min nachweisen lässt. Die kovalente Bindung der Aptamer-Kappe an das Siliciumdioxid-Gerüst ermöglichte den Verschluss der Poren durch nicht-kovalente elektrostatische Wechselwirkungen mit Oberflächen-Aminogruppen. Die Bindung von Penicillin führte zu einer Faltung des Aptamers, wodurch der zuvor in das Material geladene ECL-Reporter Ru(bpy)32+ freigesetzt wurde und nach lateralem Fluss von einer Smartphone-Kamera nach elektrochemischer Anregung mit einer in einen 3D-gedruckten Halter eingesetzten Siebdruckelektrode detektiert wird. Der Ansatz ist einfach, generisch und bietet Vorteile hinsichtlich Empfindlichkeit, Messunsicherheit und Robustheit gegenüber konventioneller Fluoreszenz- oder elektrochemischer Detektion, insbesondere für Point-of-Need-Analysen anspruchsvoller Matrices und Analyten im Ultraspurenbereich. KW - Schnelltests KW - Elektrochemilumineszenz KW - Aptamere KW - Teststreifen KW - Gesteuerte Freisetzung PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540205 DO - https://doi.org/10.1002/ange.202110744 VL - 133 IS - 50 SP - 26491 EP - 26501 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54020 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tobias, Charlie A1 - Climent Terol, Estela A1 - Gotor, Raúl A1 - Bell, Jérémy A1 - Rurack, Knut T1 - Dip-stick coated with Polystyrene-Silica Core-Shell particles for the detection of microbiological fuel contamination N2 - The microbial contamination of fuels by fungi or bacteria presents risks such as corrosion and fuel system fouling, which can produce critical problems in refineries and distribution systems and has a significant economic impact at every phase of the process. Many factors have been cited as responsible for microbial growth, like the presence of water in the storage tanks. Indeed, only 1 % water in a storage system is enough for the growth of microorganisms like bacteria or yeasts, as well as for the development of fungal biomass at the oil/water interface.1 In this work, a rapid test for the accurate determination of genomic DNA from aqueous fuel extracts is presented. The detection is based on the employment of polystyrene-mesoporous silica core-shell particles, on which modified fluorescent molecular beacons are covalently grafted. Those beacons incorporate in the hairpin loop a target sequence highly conserved in all bacteria, corresponding to a fragment of the 16S ribosomal RNA subunit. The designed single-stranded molecular beacon contained fluorescein as an internal indicator and a quencher in its proximity when not hybridized. Upon hybridization in presence of the target sequence, the indicator and the quencher are spatially separated, resulting in fluorescence enhancement. To perform the assay the designed particles were disposed on different glass fiber strips to try to achieve a portable and sensitive rapid test. Assays showed that presence of genomic DNA extracts from bacteria down to 50–70 μg L-1 induces a fluorescence response. The optical read-out was adapted for on-site monitoring by adapting a 3D-printed case on a conventional smartphone, taking advantages of the CMOS detector sensitivity.2 Such embedded assembly allowed to detect genomic DNA in aqueous extracts down to the mg L-1 range and presents an interesting step toward on-site monitoring of fuel contamination. T2 - Europtrode 2021 CY - Warsaw, Poland DA - 28.11.2021 KW - Bacgteria KW - Fungi KW - Rapid test KW - Fluorescence KW - Smartphone KW - Biofouling PY - 2021 AN - OPUS4-53867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Reaction-based BODIPY dyes as powerful tools in fluorescence sensing applications N2 - The reversible analyte-induced switching between a colourless leuco form of a dye and its coloured all-π-conjugated form is one of the oldest concepts in probe- or indicator-based optical analysis,1 constituting so-called “one-color indicators”.2 In contrast to colour changes in the visible region, for which usually a bond-forming or a non-covalent interaction between a functional group on an indicator and an analyte is responsible, the extraordinarily large shifts of 150–250 nm seen for leuco-to-all-π-conjugated transformation are only possible when the reaction takes place directly at a site that is an intrinsic part of a dye’s π-system; the classic case are triphenylmethane dyes.3 Despite its obvious potential, this approach has not been a very popular area of scientific research for decades, perhaps because it is much more difficult to implement selectivity than by modifying terminal functional groups. However, in recent years, reaction-based fluorescence probes have attracted increasing attention by virtue of their superior sensitivity.4,5 Nowadays, rhodamines and fluoresceins are by far the most prominent groups of reaction-based indicators.5 They are usually switched between a colourless and non-fluorescent and a greenish-yellowish absorbing and yellowish-reddish emitting form. Typically, the coloured and fluorescent form is ionic, while the colourless form is neutral, reactions having mainly be designed to occur at the end groups of the xanthenoid π-system. BODIPY dyes, with their favourable spectroscopic and chemical properties as well as facile wavelength tunability features have only very recently been explored into this direction.6,7 Reaction at the core dipyrrin framework of these dyes led to strong colour and fluorescence modulations with potential applications in materials sciences6 and cell imaging.7 The present contribution will highlight the mechanisms at play and the sensing performance realized so far, and will compare core-reactive approaches to reaction-based signalling that involves π-extension of BODIPYs.8,9 T2 - 11th International Conference on Porphyrins and Phthalocyanines (ICPP-11) CY - Online meeting DA - 26.06.2021 KW - Indicators KW - Fluorescence KW - Sensing KW - BODIPY Dyes PY - 2021 AN - OPUS4-54001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Approaches to Sensitive and Multiplexed Assays for Robust, Reliable and User-friendly Point-of-Need Analysis N2 - Analytical assays that can be used outside of a dedicated laboratory environment have received unprecedented attention all around the globe during the last one and a half years, in which the world was struggling with and trying to contain the SARS-CoV-2 pandemic. However, besides their current prominence in the field of medical diagnostics, rapid tests and assays have also become increasingly important in other areas ranging from food and feed via security and forensics to environmental management. The advantage is obvious: taking the assay to the sample instead of bringing the sample to the laboratory minimizes the time between first suspicion and first decision taking. Especially today, where mobile communication devices with powerful computing capabilities and onboard cameras are omnipresent, the majority of the global population possesses the basic skills of operating a powerful detector, ready at their fingertips. The stage is thus set for a much broader use of analytical measurements in terms of prognostics and prevention. Today, however, tests for single parameters are still prevailing, whether it is a SARS-CoV-2 biomarker, the glucose level in blood or the concentration of lead in a water sample. Also, for industrial use, many mobile analytical systems still target a single parameter, and several separate runs or tests have to be used even if one wants to screen for only a small number of key parameters. Current challenges in the field thus lie with the development of low-number multiplexing strategies while allowing for robust, reliable, fast, and user-friendly operation and while still reaching the required sensitivities. This lecture will give an overview of various generic approaches developed in BAM’s Chemical and Optical Sensing Division over the years to address these challenges. In particular, it will highlight how the combination of supramolecular (bio)chemistry, luminescence detection, hybrid (nano)materials and device miniaturization can result in powerful (bio)analytical assays that can be used at a point-of-need. Selected examples will introduce key aspects of such systems like tailored signaling mechanisms and recognition elements, materials functionalization and device integration, including hybrid mesoporous nanomaterials, gated indicator release systems, molecularly imprinted polymers, microfluidic devices, test strips and smartphone-based analysis. T2 - Advanced Analytical Technologies Seminar CY - Online meeting DA - 08.12.2021 KW - Rapid tests KW - Multiplexing KW - Trace analysis PY - 2021 AN - OPUS4-54002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sun, Yijuan A1 - Gawlitza, Kornelia A1 - Valderrey, Virginia A1 - Rurack, Knut T1 - Molecularly Imprinted Polymer Embedded BODIPY Probes for the Fluorescence Detection of Antibiotics N2 - Antibiotics are widely used to combat bacterial infections in humans and animals and their use has greatly improved modern healthcare. However, frequent and reckless use of antibiotics can cause antibiotic resistance in bacteria and pollute ecosystems. Therefore, the rapid and reliable detection of antibiotics is crucial. Fluorescence sensing is particularly attractive because of its high sensitivity and low limits of detection. Fluorescence assays can be carried out in a variety of platforms such as strips and particles among others. Recently, core-shell molecularly imprinted polymers (MIPs) have emerged as a promising sensor platform for (bio)chemical detection due to their low-cost, high stability, reusability, high affinity and selectivity.MIPs in combination with fluorescent molecular probes are gorgeous, since the covalently embedded probe allows for direct indication of a rebound template and provides a wealth of information about the binding state of a MIP through the multitude of fluorescence parameters accessible, facilitating MIP optimization. In the present work, we have developed a novel series of fluorescent functional monomers, which consist of a fluorophore with a π-conjugated urea recognition site and one or two polymerizable units. The fluorescent monomers are covalently embedded into the MIP matrix to generate fluorescence changes upon template binding (Figure 1). Preliminary titrations of the dye monomer with the analytes show a blue shift of the absorption spectrum and a decrease in the fluorescence intensity which confirms the formation of hydrogen bonds between the urea and the carboxylate group of the antibiotic. Compared with the non-imprinted polymers, the MIP shells on core carrier particles have demonstrated an effective imprinting by showing a higher fluorescence response upon analyte binding. T2 - EUROPT(R)ODE2021 CY - Warsaw, Poland DA - 28.11.2021 KW - Antibiotics KW - Fluorescent dye KW - Molecularly Imprinted Polymer PY - 2021 AN - OPUS4-53891 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pérez-Padilla, Victor A1 - Kimani, Martha Wamaitha A1 - Valderrey, Virginia A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Fluorescent molecularly imprinted polymer particles for detection of environmental contaminants N2 - Analysis of environmental contaminants such as pesticides is increasing in importance due to frequent detection of residues in water reserves and food stuff, as well as lowering of maximum residue levels (MRLs). Molecularly imprinted polymers (MIPs) have been developed for preconcentration of these analytes prior to analysis by chromatographic techniques. MIPs are prepared by polymerization of monomers in a matrix containing the analyte, followed by extraction of the analyte to obtain binding sites that are complementary to the analyte of interest. Recently, our group developed MIPs containing fluorescent reporter molecules that can be used for direct detection and quantification of 2,4-D in contaminated water. Core/shell MIP particles were employed, consisting of submicron silica nanoparticles coated with a MIP shell containing a fluorescent reporter whose signal was enhanced upon binding with 2,4-D in water. A limit of detection of 20 nM was attained. We present here a comparable system, composed of fluorescent core-shell MIPs for the direct analysis of pesticides in environmental samples. T2 - Europtrode 2021 CY - Warsaw, Poland DA - 29.11.2021 KW - Glyphosate KW - Guanidinium Receptors KW - Fluorescent Probes KW - Molecularly Imprinted Polymers KW - Core-Shell Particles PY - 2021 AN - OPUS4-53878 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hülagü, Deniz A1 - Tobias, Charlie A1 - Gojani, Ardian A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan T1 - Analysis of the profile roughness of core-shell microparticles by electron microscopy N2 - A particle roughness analysis tool, based on electron microscopy (EM) images. The influence of various parameters on the calculated roughness was also investigated: the setting of the proper threshold, accelerating voltage, etc. The samples were gradually tilted to extend imaging information of more than only one projection. Furthermore, the measurement uncertainty of the profile roughness of particles associated to various orientations was estimated. T2 - Microscopy and Microanalysis 2021 CY - Online Meeting DA - 01.08.2021 KW - MamaLoCA KW - Particle characterization KW - Electron microscopy KW - Roughness KW - Core-shell particles KW - Image processing PY - 2021 AN - OPUS4-53069 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gojani, Ardian A1 - Tobias, Charlie A1 - Hülagü, Deniz A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan T1 - Toward Determination of the Surface Roughness of Particles from a SEM Image N2 - Welcome to the poster Towards Determination of Surface Roughness from a SEM Image, a contribution from BAM in Berlin, Germany. This work is part of the MamaLoCA project, which aims to develop a biosensor for the detection of mycotoxins in cereals. Biosensors come in a great variety, one of which makes use of microscopic beads produced by homogenous coating of polystyrene microspheres. The beads are functionalized by decorating them with bioreceptors – in our case antibodies – which then specifically react with the analyte – in our case mycotoxins – and emit an electrical or optical signal. The functionalization of the beads depends on the surface roughness because this determines the amount and orientation of binders. In other words, the surface roughness affects the accessibility to the binding sites and influences device sensitivity, hence its quantitative determination is an important step in evaluating the quality of the biosensor in general. The presented solution to the problem of the estimation of surface roughness relies in the repetitive characteristics on the surface of the beads. A SEM image of the bead shows a raspberry like microparticle with a variation of grayscale values, which arise from the secondary electron yield. The principle of the measurement measures the variation of grayscale values along a circumference of a circle centred in the centre of the particle and with an arbitrary radius. The grayscale value variation along the given circumference gives the so-called z-modulation or the lateral profile. By performing Fast Fourier Transform on this profile we obtain the power spectrum as a function of the spatial frequencies through which the grayscales vary. The maximal value for spatial frequency then reveals the most common feature along one given circumference. Surface roughness then is the feature frequency in the spatial domain. This calculation is repeated for several concentric circles with different radii over the particle. The results for the same particle but recorded at two different accelerating voltages show that the applied method has a potential to reveal the roughness. Interpretation of results from an SE InLens SEM image obtained using 3 kV shows that surface roughness is about 21 nm, which is in a good agreement with an alternative method given in a different presentation. The results from the 10 kV are underestimated due to the loss of surface sensitivity on the SE InLens detection at high voltages. In conclusion, this method shows promise in determining quantitatively the surface roughness from a single SEM image and its validation is being sought using 3D SEM images and AFM methods. T2 - Microscopy and Microanalysis 2021 CY - Online Meeting DA - 01.08.2021 KW - MamaLoCA KW - Core-shell particles KW - Electron microscopy KW - Image processing KW - Particle characterisation KW - Roughness KW - Fast Fourier Transform PY - 2021 AN - OPUS4-53089 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hülagü, Deniz A1 - Tobias, Charlie A1 - Gojani, Ardian A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan T1 - Analysis of the profile roughness of core-shell microparticles by electron microscopy N2 - A particle roughness analysis tool, based on electron microscopy images (SEM and TEM). The influence of various parameters on the calculated roughness was also investigated: the setting of the proper threshold, accelerating voltage, etc. The samples were gradually tilted to extend imaging information of more than only one projection. Furthermore, the measurement uncertainty of the profile roughness of particles associated to various orientations was estimated. KW - Core-shell particles KW - Electron microscopy KW - Image processing KW - MamaLoCa KW - Particle Characterization KW - Roughness PY - 2021 DO - https://doi.org/10.1017/S1431927621007285 VL - 27 IS - Suppl. 1 SP - 2002 EP - 2004 PB - Cambridge University Press AN - OPUS4-53123 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maher, C. A1 - Schazmann, B. A1 - Gornushkin, Igor B. A1 - Rurack, Knut A1 - Gojani, Ardian T1 - Exploring an Application of Principal Component Analysis to LaserInduced Breakdown Spectroscopy of Stainless-Steel Standard Samples as a Research Project N2 - Laser-induced breakdown spectroscopy (LIBS) and principal component analysis (PCA) are frequently used for analytical purposes in research and industry, but they seldom are part of the chemistry Curriculum or laboratory exercises. This case study paper describes the combined application of LIBS and PCA during a research internship for an undergraduate student. The instructional method applied was based on a one-on-one mentorship, in which case the learner was engaged in a Research work. The learning activities included theoretical introductions to the LIBS and PCA methods, numerical simulation, experiments, and data analysis. The study covered three main topics: analysis of LIBS spectra, application of PCA for clustering, and use of PCA for experimental design. The realization of the study was instructive for all parties involved: from the mentorship point of view, it is concluded that the topics can be covered during an internship or developed into a one semester long research-based module of a chemistry program or a final year project. The student, on the other hand, developed profound technical skills in performing experiments and using PCA software for data analysis. KW - LIBS KW - PCA PY - 2021 DO - https://doi.org/10.1021/acs.jchemed.1c00563 VL - 98 SP - 3237 EP - 3244 PB - American Chemical Society Publications CY - USA AN - OPUS4-53515 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Climent Terol, Estela A1 - Rurack, Knut A1 - Hecht, Mandy T1 - Loading and Release of Charged and Neutral Fluorescent Dyes into and from Mesoporous Materials: A Key Role for Sensing Applications N2 - The aim of this study is to determine the efficiency of loading and release of several zwitterionic, neutral, anionic and cationic dyes into/from mesoporous nanoparticles to find the optimum loading and release conditions for their application in detection protocols. The loading is carried out for MCM-41 type silica supports suspended in phosphate-buffered saline (PBS) buffer (pH 7.4) or in acetonitrile, involving the dyes (rhodamine B chloride, rhodamine 101 chloride, rhodamine 101 perchlorate, rhodamine 101 inner salt, meso-(4-hydroxyphenyl)-boron–dipyrromethene (BODIPY), sulforhodamine B sodium salt and fluorescein 27). As a general trend, rhodamine-based dyes are loaded with higher efficiency, when compared with BODIPY and fluorescein dyes. Between the rhodamine-based dyes, their charge and the solvent in which the loading process is carried out play important roles for the amount of cargo that can be loaded into the materials. The delivery experiments carried out in PBS buffer at pH 7.4 reveal for all the materials that anionic dyes are more efficiently released compared to their neutral or cationic counterparts. The overall best performance is achieved with the negatively charged sulforhodamine B dye in acetonitrile. This material also shows a high delivery degree in PBS buffer. KW - Mesoporous materials KW - Charged dyes KW - Neutral dyes KW - Dye loading optimisation KW - Dye release PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522596 UR - https://www.mdpi.com/2072-666X/12/3/249 DO - https://doi.org/10.3390/mi12030249 VL - 12 IS - 3 SP - 249 PB - MDPI AN - OPUS4-52259 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Climent Terol, Estela A1 - Rurack, Knut T1 - Combining electrochemiluminescence detection with aptamer-gated indicator releasing mesoporous nanoparticles enables ppt sensitivity for strip-based rapid tests N2 - The combination of electrogenerated chemiluminescence (ECL) and aptamer-gated indicator delivering (gAID) magnetic mesoporous silica nanoparticles embedded into glass fibre paper functionalised with poly(ethyleneglycol) and N-(3-triethoxysilylpropyl)diethanolamine allowed the development of a rapid test that detects penicillin directly in diluted milk down to 50 ± 9 ppt in <5 min. Covalent attachment of the aptamer ‘cap’ to the silica scaffold enabled pore closure through non-covalent electrostatic interactions with surface amino groups, while binding of penicillin led to a folding-up of the aptamer thus releasing the ECL reporter Ru(bpy)32+ previously loaded into the material and letting it be detected after lateral flow by a smartphone camera upon electrochemical excitation with a screen printed electrode inserted into a 3D-printed holder. The approach is simple, generic and presents advantages with respect to sensitivity, measurement uncertainty and robustness compared with conventional fluorescence or electrochemical detection, especially for point-of-need analyses of challenging matrices and analytes at ultra-trace levels. KW - Electrochemiluminiscence KW - Hybrid materials KW - Signal amplification KW - Test strip analysis KW - Penicillin PY - 2021 DO - https://doi.org/10.1002/anie.202110744 SN - 1433-7851 SN - 1521-3773 SP - 1 EP - 11 PB - Wiley-VCH CY - Weinheim AN - OPUS4-53447 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. A1 - Veiko, V. P. A1 - Karlagina, J. J. A1 - Polyakov, D. S. A1 - Samokhvalov, A. A. T1 - Reverse deposition of TI-oxides under nanosecond laser ablation of TI N2 - Processes of laser induced oxidation of metals are typically studied in the framework of heterogeneous chemical reactions occurring on the irradiated surface, which lead to the formation of dense oxide films deposited on it. Such technology has many applications like color-laser marking technology and laser recording on thin metal films for creation of diffractive optical elements . Under the conditions of strong laser ablation, another oxidation mechanism becomes possible: evaporated atoms react with oxygen in a surrounding atmosphere and the products of such reaction are redeposited back onto the substrate. The chemical and phase composition of such deposited layer, its density, morphology and structure depend on the conditions of laser ablation. By varying these conditions, the main properties of such coating can be controlled that is important for some potential application (for example in biomedicine). In our report we present the study of the processes of redeposition of oxides structure under the conditions of multipulse nanosecond laser ablation of titanium (Grade 2) in air atmosphere at normal conditions. Our experiments show that titanium-implants with such deposited oxide layer have increased biocompatibility. Modelling of chemical reaction in laser-induced plasma coupled with experimental methods of plasma optical emission spectroscopy allows us to determine the types of main chemical reactions in laser plasma as well as it influences on the plume dynamics and vapor condensation kinetics. As a result, we propose the general physical picture of reverse deposition of oxides structure under the condition of strong nanosecond laser ablation. The formation of the titanium oxide precipitate is explained not only by collisions in the plasma, but also by the chemical interaction of titanium and oxygen, which leads to the formation of а low pressure area near the substrate and additionally stimulates the reverse deposition of oxides. We expect, similar processes are valid not only for titanium but also for other metals and, possibly, semiconductors. T2 - 28th International Conference on Advanced Laser Technologies CY - Online meeting DA - 06.09.2021 KW - Laser ablation KW - Laser induced plasma deposition KW - Surface coating KW - Emission spectroscopy KW - Titanium dioxide KW - Hydrodynamic model KW - Plasma chemistry PY - 2021 AN - OPUS4-53245 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. A1 - Pignatelli, Giuseppe A1 - Straße, Anne T1 - Optical Detection of Defects during Laser Metal Deposition - Simulations and Experiment N2 - Laser metal deposition is a rapidly evolving method for additive manufacturing that combines high performance and simplified production routine. Quality of production depends on instrumental design and operational parameters that require constant control during the process. In this work, feasibility of using optical spectroscopy as a control method is studied via modeling and experimentally. A simplified thermal model is developed based on the time-dependent diffusion-conduction heat equation and geometrical light collection into detection optics. Intense light emitted by a laser-heated spot moving across a sample surface is collected and processed to yield the temperature and other temperature-related parameters. In a presence of surface defects the temperature field is distorted in a specific manner that depends on a shape and size of the defect. Optical signals produced by such the distorted temperature fields are simulated and verified experimentally using a 3D metal printer and a sample with artificially carved defects. Three quantities are tested as possible metrics for process monitoring: temperature, integral intensity, and correlation coefficient. The shapes of the simulated signals qualitatively agree with the experimental signals; this allows a cautious inference that optical spectroscopy is capable of detecting a defect and, possibly, predicting its character, e.g. inner or protruding. T2 - 28th International Conference on Advanced Laser Technologies CY - Online meeting DA - 06.09.2021 KW - Additive manufacturing KW - Laser metal deposition KW - Optical sensor KW - Optical emission spectroscopy KW - Process control PY - 2021 AN - OPUS4-53246 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gawlitza, Kornelia A1 - Johann, Sergej A1 - Mansurova, Maria A1 - Kohlhoff, Harald A1 - Tiebe, Carlo A1 - Bell, Jérémy A1 - Bartholmai, Matthias A1 - Rurack, Knut T1 - Semi-automatic Measurement Device for Long-Term Monitoring of Ammonia in Gas Phase N2 - In the present paper the development of a semi-automated device for long-term monitoring of gaseous ammonia is described. A sensor material was produced that changes its optical properties in the pres-ence of low concentrations of ammonia in air. The implementation into an electronic device enables precise, simple, economic and fast monitoring of low concentrations of harmful gases, like ammonia, and hence can help to improve the climate monitoring in livestock housing, barns or stables. T2 - SMSI 2021 CY - Online meeting DA - 03.05.2021 KW - Spectroscopy KW - Embedded sensor KW - Environment KW - Air quality PY - 2021 SP - 133 EP - 134 AN - OPUS4-52576 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gawlitza, Kornelia A1 - Johann, Sergej A1 - Mansurova, Maria A1 - Kohlhoff, Harald A1 - Tiebe, Carlo A1 - Bell, Jérémy A1 - Bartholmai, Matthias A1 - Rurack, Knut T1 - Long-Term Monitoring of Gaseous Ammonia with a Semi-automated Measuring Device N2 - In the present paper the development of a semi-automated device for long-term monitoring of gaseous ammonia is described. A sensor material was produced that changes its optical properties in the pres-ence of low concentrations of ammonia in air. The implementation into an electronic device enables precise, simple, economic and fast monitoring of low concentrations of harmful gases, like ammonia, and hence can help to improve the climate monitoring in livestock housing, barns or stables. T2 - SMSI 2021 CY - Online meeting DA - 03.05.2021 KW - Spectroscopy KW - Embedded sensor KW - Environment KW - Air quality PY - 2021 AN - OPUS4-52575 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jiang, Shan A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Dual-Fluorescent Nanoparticle Probes Consisting of a Carbon Nanodot Core and a Molecularly Imprinted Polymer Shell N2 - Dual-fluorescent molecularly imprinted nanoparticles with a red-emissive carbon nanodot-doped silica core and a chlorogenic acid-imprinted fluorescent polymer layer are prepared and their use in ratiometric fluorometric analysis is described. Nanoparticle probes consisting of a shielded and stably emitting core and a shell with embedded binding sites that indicates the presence of an analyte with a change in emission allow for internally referenced measurements potentially accounting for detrimental influences from instrument drifts, light source fluctuations or sensor materials-related inhomogeneities. KW - Molecular imprinting KW - Fluorescence KW - Core-shell particles KW - Chlorogenic acid KW - Ratiometric measurement PY - 2021 DO - https://doi.org/10.1007/978-1-0716-1629-1_17 VL - 2359 SP - 195 EP - 208 PB - Springer CY - Humana, New York, NY AN - OPUS4-53336 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gojani, Ardian A1 - Tobias, Charlie A1 - Hülagü, Deniz A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan T1 - Toward determination of the surface roughness of particles from a SEM image N2 - In this communication, we address the issue of roughness measurement by investigating if the grayscale values from SEM images can be used for surface roughness determination of spherical particles. KW - MamaLoCA KW - Core-shell particles KW - Electron microscopy KW - Image processing KW - Particle characterisation KW - Roughness PY - 2021 DO - https://doi.org/10.1017/S1431927621011375 SN - 1431-9276 SN - 1435-8115 VL - 27 IS - Suplement S1 SP - 3302 EP - 3305 PB - Cambridge University Press CY - New York, NY AN - OPUS4-53283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Pignatelli, Giuseppe A1 - Strasse, Anne T1 - Optical detection of defects during laser metal deposition: Simulations and experiment N2 - Laser metal deposition is a rapidly evolving method for additive manufacturing that combines high performance and simplified production routine. Quality of production depends on instrumental design and operational parameters that require constant control during the process. In this work, feasibility of using optical spectroscopy as a control method is studied via modeling and experimentally. A simplified thermal model is developed based on the time-dependent diffusion-conduction heat equation and geometrical light collection into detection optics. Intense light emitted by a laser-heated spot moving across a sample surface is collected and processed to yield the temperature and other temperature-related parameters. In a presence of surface defects the temperature field is distorted in a specific manner that depends on a shape and size of the defect. Optical signals produced by such the distorted temperature fields are simulated and verified experimentally using a 3D metal printer and a sample with artificially carved defects. Three quantities are tested as possible metrics for process monitoring: temperature, integral intensity, and correlation coefficient. The shapes of the simulated signals qualitatively agree with the experimental signals; this allows a cautious inference that optical spectroscopy is capable of detecting a defect and, possibly, predicting its character, e.g. inner or protruding. KW - Additive manufacturing KW - Laser metal deposition (LMD) KW - Thermal model KW - Optical sensor KW - Process control PY - 2021 DO - https://doi.org/10.1016/j.apsusc.2021.151214 SN - 0169-4332 VL - 570 SP - 1 EP - 13 PB - Elsevier CY - Amsterdam AN - OPUS4-53292 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Climent Terol, Estela A1 - Wan, Wei A1 - Rurack, Knut T1 - Toward Label-Free Optical Multiplexing of Analytes in Indicator Release Lateral Flow Assays via Detection Zones Containing Tailored Capture Materials N2 - The use of macromolecules and materials immobilized in the detection zone of test strips for indicator capture and focusing in label-free lateral flow assays (LFAs) is described, with emphasis on its future use in low number multiplexing. Several materials such as polyelectrolytes, functionalized mesoporous silica micro- and nanoparticles, chemically modified cellulose or glass fibre (GF) membranes and molecularly imprinted polymer gels coated onto membranes were studied in model assays, before the most promising materials were combined with antibody-gated indicator delivering (gAID) sensor materials. Cellulose, nitrocellulose and GF membranes were used as supports and highly fluorescent dyes of different charge states as model indicators. Combination of the best performing capture materials with gAID systems made it possible to distinctly increase the sensitivity and reduce the measurement uncertainty in the LFA testing of pentaerythritol tetranitrate (PETN) in aqueous samples. In addition, dual-plexing of PETN and 2,4,6-trinitrotoluene (TNT) was realized on a single test strip containing two dedicated capture zones. KW - Rapid tests KW - Vor-Ort-Analytik KW - Multiplexing KW - Teststreifen KW - Molecularly imprinted polymers PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557873 DO - https://doi.org/10.1002/anse.202100062 VL - 2 IS - 4 SP - 1 EP - 10 PB - Wiley-VCH CY - Weinheim AN - OPUS4-55787 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hülagü, Deniz A1 - Tobias, Charlie A1 - Benemann, Sigrid A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan T1 - From 2D and Single Particle to 3D and Batch Analysis as a Routine Quality Check Procedure for the Morphological Characterization of Core-Shell Microparticles N2 - This study presents a practical procedure to give access to more information by tilting the sample holder and hence allowing images of a single particle to be recorded at different orientations under the same view angle. From the analysis of these images, extended information on surface roughness of the particle can be extracted. Thus, instead of obtaining 2D information from a single SEM image, three-dimensional (3D) information is obtained from 2D projections recorded at different particle orientations. T2 - Microscopy & Microanalysis 2022 CY - Online meeting DA - 31.07.2022 KW - Core-shell particles KW - 3D image analysis KW - Roughness KW - SEM tilting KW - Batch analysis PY - 2022 AN - OPUS4-55452 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kimani, Martha Wamaitha A1 - Kislenko, Evgeniia A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Fluorescent molecularly imprinted polymer particles for glyphosate detection using phase transfer agents N2 - In this work, molecular imprinting was combined with direct fluorescence detection of the pesticide Glyphosate (GPS). Firstly, the solubility of highly polar GPS in organic solvents was improved by using lipophilic tetrabutylammonium (TBA+) and tetrahexylammonium (THA+) counterions. Secondly, to achieve fluorescence detection, a fluorescent crosslinker containing urea-binding motifs was used as a probe for GPS-TBA and GPS-THA salts in chloroform, generating stable complexes through hydrogen bond formation. The GPS/fluorescent dye complexes were imprinted into 2–3 nm fluorescent molecularly imprinted polymer (MIP) shells on the surface of sub-micron silica particles using chloroform as porogen. Thus, the MIP binding behavior could be easily evaluated by fluorescence titrations in suspension to monitor the spectral changes upon addition of the GPS analytes. While MIPs prepared with GPS-TBA and GPS-THA both displayed satisfactory imprinting following titration with the corresponding analytes in chloroform, GPS-THA MIPs displayed better selectivity against competing molecules. Moreover, the THA+ counterion was found to be a more powerful phase transfer agent than TBA+ in a biphasic assay, enabling the direct fluorescence detection and quantification of GPS in water. A limit of detection of 1.45 μM and a linear range of 5–55 μM were obtained, which match well with WHO guidelines for the acceptable daily intake of GPS in water (5.32 μM). KW - Glyphosate KW - Molecular imprinting KW - Core-shell particles KW - Fluorescent sensors PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555281 DO - https://doi.org/10.1038/s41598-022-16825-9 SN - 2045-2322 VL - 12 IS - 1 SP - 1 EP - 15 PB - Macmillan Publishers Limited CY - London AN - OPUS4-55528 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hülagü, Deniz A1 - Tobias, Charlie A1 - Gojani, Ardian B. A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan T1 - From 2D and Single Particle to 3D and Batch Analysis as a Routine Quality Check Procedure for the Morphological Characterization of Core-Shell Microparticles N2 - CS particles show unique properties by merging individual characteristics of the core and the shell materials. An alteration particularly in their surface roughness affects the final performance of the particles in the targeted application. Quantitative evaluation of the roughness of CS microparticles is, however, a challenging task employing microscopic techniques being scarce and showing large differences in terms of methodology and results. In our previous work, we have reported a systematic study with a reliable analysis tool, which evaluates profile roughness quantitatively, for individual core-shell microparticles using electron microscopy (EM) images of both types, Scanning Electron Microscopy (SEM) and transmission mode SEM (or TSEM). The SEM images contain two-dimensional (2D) information, therefore, provide profile roughness data only from the projection in the horizontal plane (in other words, from the “belly”) of a spherical particle. The present study offers a practical procedure to give access to more information by tilting the sample holder and hence allowing images of a single particle to be recorded at different orientations under the same view angle. From the analysis of these images, extended information on surface roughness of the particle can be extracted. Thus, instead of obtaining 2D information from a single SEM image, three-dimensional (3D) information is obtained from 2D projections recorded at different particle orientations. T2 - Microscopy and Microanalysis 2022 CY - Oregon, Portland, USA DA - 31.07.2022 KW - Core-shell particles KW - Image processing KW - Roughness KW - Scanning electron microscopy KW - Tilting PY - 2022 DO - https://doi.org/10.1017/S1431927622002094 SN - 1431-9276 VL - 28 IS - S1 SP - 332 EP - 334 PB - Cambridge University Press AN - OPUS4-55373 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Garrido, E. A1 - Climent Terol, Estela A1 - Marcos, M. D. A1 - Sancenón, F. A1 - Rurack, Knut A1 - Martínez-Máñez, R. T1 - Dualplex lateral flow assay for simultaneous scopolamine and "cannibal drug" detection based on receptor-gated mesoporous nanoparticles N2 - We report herein the design of a strip-based rapid test utilizing bioinspired hybrid nanomaterials for the in situ and at site detection of the drug scopolamine (SCP) using a smartphone for readout, allowing SCP identification in diluted saliva down to 40 nM in less than 15 min. For this purpose, we prepared a nanosensor based on mesoporous silica nanoparticles loaded with a fluorescent reporter (rhodamine B) and functionalized with bethanechol, a potent agonist of recombinant human muscarinic acetylcholine receptor M2 (M2-AChR). M2-AChR interaction with the anchored bethanechol derivative leads to capping of the pores. The sensing mechanism relies on binding of SCP to M2-AChR resulting in pore opening and delivery of the entrapped rhodamine B reporter. Moreover, the material was incorporated into strips for lateral-flow assays coupled to smartphone readout, giving fast response time, good selectivity, and exceptional sensitivity. In an attempt to a mobile analytical test system for law enforcement services, we have also developed a dualplex lateral flow assay for SCP and 3,4-methylenedioxypyrovalerone (MDPV) also known as the so-called “cannibal drug”. KW - Rapid tests KW - Vor-Ort-Analytik KW - Lateral Flow Assays KW - Scopolamine KW - Gesteuerte Freisetzung KW - Cannibal Drug PY - 2022 DO - https://doi.org/10.1039/d2nr03325a SP - 1 EP - 9 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-55744 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ruhe, L. A1 - Ickert, Stefanie A1 - Beck, S. A1 - Linscheid, M. W. T1 - A new strategy for metal labeling of glycan structures in antibodies N2 - Quantitative analysis of complex proteins is a challenging task in modern bioanalytical chemistry. Commonly available isotope labels are still suffering from limitations and drawbacks, whereas new metal labels open numerous possibilities in mass spectrometric analyses. In this work, we have developed a newmetal labeling strategy to tag glycan structures of proteins, more particularly antibodies. The oligosaccharide glycans were selectively trimmed to the last N-acetylglucosamine to which an artificial azide containing galactose residue was bound. This azide can be used for subsequent cycloaddition of an alkyne. Therefore, we developed a lanthanide-containing macrocyclic reagent to selectively connect to this azido galactose. In summary, the glycan structures of an antibody can be labeled with a metal functionality using this approach. Furthermore, the functionality of the antibodies can be fully maintained by labeling the Fc glycans instead of using labeling reagents that target amino or thiol groups. This approach enables the possibility of using elemental, besides molecular mass spectrometry, for quantitative analyses or imaging experiments of antibodies in complex biological samples. KW - Antibody KW - Metal labeling KW - Glycans KW - DOTA KW - Lanthanide PY - 2018 DO - https://doi.org/10.1007/s00216-017-0683-1 SN - 1618-2650 SN - 1618-2642 VL - 410 IS - 1 SP - 21 EP - 25 PB - Springer AN - OPUS4-44000 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nagli, L. A1 - Gaft, M. A1 - Raichlin, Y. A1 - Gornushkin, Igor B. T1 - Cascade generation in Al laser induced plasma N2 - We found cascade IR generation in Al laser induced plasma. This generation includes doublet transitions 3s25s 2S1∕2→ 3s24p 2P1∕2,3∕2 → 3s24s 2S1∕2; corresponding to strong lines at 2110 and 2117 nm, and much weaker lines at 1312–1315 nm. The 3s25s2S 1∕2 starting IR generation level is directly pumped from the 3s23p 2P3∕2 ground level. The starting level for UV generation at 396.2 nm (transitions 3s24s 2S1∕2 → 4p 2P3∕2) is populated due to the fast collisional processes in the plasma plume. These differences led to different time and special dependences on the lasing in the IR and UV spectral range within the aluminum laser induced plasma. KW - Plasma diagnostics KW - Laser induced plasma KW - LIBS KW - Plasma modeling PY - 2018 DO - https://doi.org/10.1016/j.optcom.2018.01.041 VL - 415 SP - 127 EP - 129 PB - Elsevier B.V. AN - OPUS4-44274 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Plasma Fundamentals and Diagnostics N2 - This course will provide an introduction to plasma diagnostic techniques. The major focus of the course will be on the discussions of the practical procedures as well as the underlying physical principles for the measurements of plasma fundamental characteristics (e.g., temperatures, thermodynamic properties, and electron number density). Particular emphasis will be placed on inductively coupled plasma–atomic emission spectrometry, but other analytical plasmas will also be used as examples when appropriate. Selected examples on how one can manipulate the operating conditions of the plasma source, based on the results of plasma diagnostic measurements, to improve its performance used for spectrochemical analysis will also be covered. Topics to be covered include thermal equilibrium, line profiles, temperatures, electron densities, excitation processes, microreactions, pump and probe diagnostics, tomography, temporal and spatial resolution. Basis of plasma computer modeling will be presented. T2 - Winter Plasma Conference CY - Amelia Island, FL, USA DA - 08.01.2018 KW - Plasma diagnostics KW - Plasma physics PY - 2018 AN - OPUS4-44497 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. A1 - Shabanov, Sergej V. T1 - Modeling chemical reactions in laser-induced plasmas at local thermodynamic equilibrium N2 - Laser induced plasma (LIP) is a dynamic, short living event which presents significant difficulty for modeling. In this report, a collisional-dominated chemical model developed earlier* is expanded by the inclusion of a new method for calculation of chemical reactions. The model consists of the coupled Navier-Stokes, state, radiative transfer, material transport, and chemical equations. The latter are written in terms of atomic and molecular partition functions rather than reaction rates. Typically, a solution of such the system of chemical equations is difficult for the entire range of plasma temperatures and densities because reaction constants may vary by hundreds orders of magnitude owing to extreme plasma conditions. No numerical solver of non-linear systems of equations handles this situation with ease. We resolve the problem by using a hierarchical approach. First, we rank the reactions according to their ascendancy. Second, we exploit either the contraction or Newton-Raphson algorithms to solve the system of chemical equations. We illustrate the approach by performing a series of calculations for reacting species Si, C, N, Ca, Cl and their molecules in laser induced plasmas. T2 - Winter Plasma Conference CY - Amelia Island, FL, USA DA - 08.01.2018 KW - Plasma physics KW - Plasma diagnostics PY - 2018 AN - OPUS4-44499 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kimani, Martha Wamaitha A1 - Zhang, Y. A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Fluorescent core/shell molecularly-imprinted nanoparticles for staining sialic acid (SA) residues on tumor cells N2 - Cancer is a leading cause of death worldwide, and its early detection and resultant treatment contributes significantly to patient recovery and survival. Detection is currently based on magnetic resonance imaging and computed tomography, methods that are expensive, while processing of the results is time consuming. There is a need for low-cost cancer-detection techniques that give conclusive results in the shortest time possible. Molecularly imprinted polymers (MIPs) targeting tumor markers on cancerous cells may provide a cheaper solution for cancer detection. Thin MIP layers immobilized on particle platforms are known to give faster response times and increased selectivity in comparison to bulk MIPs. It has been reported that a fluorescent monomer can be incorporated into the MIP layer, allowing for faster detection of the target group, thus significantly shortening the turn-around time for biopsies. Changes in sialylation patterns of cell surface glycoproteins indicate malignancy. Here, we present the development of MIPs that target sialic acid-terminated glycoproteins (SA MIPs), prepared as a thin layer on a silica nanoparticle platform. A fluorescent monomer is incorporated into the MIP layer, and upon binding of the target group to the specific binding pockets in the MIP, the fluorescence signal is enhanced. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) are used for structural characterization. To validate the specificity, fluorescence changes of MIPs in the presence and absence of template are compared to their corresponding non-imprinted polymer particles (NIP). Initial binding experiments with tumor cells using fluorescence microscopy demonstrate that the presented technique shows promise as a cheaper alternative to current detection methods, while allowing for relatively shorter analysis of biopsy results. T2 - MIP 2018 CY - Hebrew University Jerusalem, Belgium House, Israel DA - 24.07.2018 KW - Sialic acid KW - MIPs KW - Fluorescence PY - 2018 AN - OPUS4-45419 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Völker, Tobias A1 - Kazakov, Alexander Ya. T1 - Extension and investigation by numerical simulations of algorithm for calibration-free laser induced breakdown spectroscopy N2 - Accuracy of calibration-free (CF) methods in laser-induced breakdown spectroscopy (LIBS) depends on experimental conditions and instrumental parameters that must match a CF LIBS model. Here, the numerical study is performed to investigate effects of various factors, such as the optical density, plasma uniformity, line overlap, noise, spectral resolution, electron density and path length on the results of CF-LIBS analyses. The effects are examined one-by-one using synthetic spectra of steel slag samples that fully comply with the mathematical model of the method. Also, the algorithm includes several new features in comparison with previously proposed CF algorithms. In particular, it removes limits on the optical thickness of spectral lines that are used for the construction of the Saha-Boltzmann plot; it retrieves the absorption path length (Plasma diameter) directly from spectral lines; it uses the more realistic Voigt line profile function instead of the Lorentzian function; and it employs the pre-calculated and tabulated thin-to-thick line ratios instead of approximating functions for selfabsorption correction. KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Plasma diagnostics KW - Calibration free LIBS PY - 2018 DO - https://doi.org/10.1016/j.sab.2018.06.011 SN - 0584-8547 VL - 147 SP - 149 EP - 163 PB - Elsevier B.V. AN - OPUS4-45340 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Improved algorithm for calibration-free laser induced breakdown spectroscopy N2 - An improved algorithm for calibration-free laser induced breakdown spectroscopy (CF LIBS) is presented which includes several novel features in comparison with previously proposed similar algorithms. In particular, it allows using spectral lines with arbitrary optical thickness for the construction of Saha-Boltzmann plots, retrieves the absorption path length (plasma diameter) directly from a spectrum, replaces the Lorentzian line profile function by the Voigt function, and allows for self-absorption correction using pre-calculated and tabulated data rather than approximating functions. The tabulated data embody the solutions of the radiative transfer equation for numerous combinations of optical thicknesses and line widths. The algorithm is thoroughly verified with synthetic spectra. T2 - 14TH European Workshop on Laser Ablation 2018 (EWLA2018) CY - Pau, France DA - June 26 - 29, 2018 KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Plasma diagnostics KW - Calibration free LIBS PY - 2018 AN - OPUS4-45343 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Laser induced plasma: Modeling, diagnostics, and applications N2 - Laser-induced plasmas are widely used in many areas of science and technology; examples include spectrochemical analysis, thin film deposition, material processing, and even jet propulsion. Several topics will be addressed. First, general phenomenology of laser-induced plasmas will be discussed. Then, a chemical model will be presented based on a coupled solution of Navier-Stokes, state, radiative transfer, material transport, and chemical (Guldberg-Waage) equations. Results of computer simulations for several chemical systems will be shown and compared to experimental observations obtained by optical imaging, spectroscopy, and tomography. The latter diagnostic tools will also be briefly discussed. Finally, a prospective application of laser-induced plasma and plasma modeling will be illustrated on the example of calibration-free MC LIBS (Monte Carlo Laser Induced Breakdown Spectroscopy), in which concentrations of elements in materials are found by fitting model-generated and experimental spectra. T2 - Invited talk at Yeshiva University, New York, USA CY - Yeshiva University, New York, USA DA - 4.24.2018 KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Plasma diagnostics PY - 2018 AN - OPUS4-45344 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lozano-Torres, B. A1 - Marcos, M. Dolores A1 - Pardo, T. A1 - Sancenón, F. A1 - Martínez-Mánez, Ramon A1 - Rurack, Knut T1 - Anilinopyridine–metal complexes for the selective chromogenic sensing of cyanide anion N2 - Probe 1, which contains an anilinopyridine chromophore and an azaoxa macrocyclic subunit, presented an absorption band centered at 340 nm in acetonitrile. Addition of Fe(III), Cr(III) and Hg(II) induced the growth of a new absorption band at 430 nm (with color change from colorless to yellow), whereas in the presence of Cu(II), Zn(II) and Pb(II), less marked changes were observed. The color changes observed upon addition of Fe(III), Cr(III) and Hg(II) were ascribed to the formation of 1:1 stoichiometry complexes with probe 1. Coordination of Fe(III), Cr(III) and Hg(II) with the pyridine fragment of 1 induced an enhancement of the charge transfer character accompanied with a marked bathochromic shift that was reflected in a color change from colorless to yellow. The strength of the interaction between probe 1 and Fe(III) cation was modulated upon interaction with anions. Of all the anions tested, only cyanide was able to induce the bleaching of the yellow 1·Fe(III) complex solution. This bleaching was ascribed to the formation of 1·Fe(III)-CN complex that restored, to some extent, the optical features of the free probe allowing the chromogenic sensing of cyanide. Besides, 1·Fe(III) complex was used to detect cyanide in acetonitrile-water 90:10 v/v mixtures with good recoveries. KW - Anilinopyridine KW - Charge Transfer KW - Iron Complex KW - Colorimetric Test KW - Cyanide PY - 2018 DO - https://doi.org/10.1080/00958972.2018.1434719 SN - 0095-8972 VL - 71 IS - 6 SP - 786 EP - 796 PB - Taylor & Francis Group CY - London AN - OPUS4-45398 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wagner, Sabine A1 - Zapata, Carlos A1 - Wan, Wei A1 - Gawlitza, Kornelia A1 - Weber, M. A1 - Rurack, Knut T1 - Role of Counterions in Molecularly Imprinted Polymers for Anionic Species N2 - Small-molecule oxoanions are often imprinted noncovalently as carboxylates into molecularly imprinted polymers (MIPs), requiring the use of an organic counterion. Popular species are either pentamethylpiperidine (PMP) as a protonatable cation or tetraalkylammonium (TXA) ions as permanent cations. The present work explores the influence of the TXA as a function of their alkyl chain length, from methyl to octyl, using UV/vis absorption, fluorescence titrations, and HPLC as well as MD simulations. Protected phenylalanines (Z-L/D-Phe) served as templates/analytes. While the influence of the counterion on the complex stability constants and anion-induced spectral changes shows a monotonous trend with increasing alkyl chain length at the prepolymerization stage, the cross-imprinting/rebinding studies showed a unique pattern that suggested the presence of adaptive cavities in the MIP matrix, related to the concept of induced fit of enzyme−substrate interaction. Larger cavities formed in the presence of larger counterions can take up pairs of Z-X-Phe and smaller TXA, eventually escaping spectroscopic detection. Correlation of the experimental data with the MD simulations revealed that counterion mobility, the relative distances between the three partners, and the hydrogen bond lifetimes are more decisive for the response features observed than actual distances between interacting atoms in a complex or the orientation of binding moieties. TBA has been found to yield the highest imprinting factor, also showing a unique dual behavior regarding the interaction with template and fluorescent monomer. Finally, interesting differences between both enantiomers have been observed in both theory and experiment, suggesting true control of enantioselectivity. The contribution concludes with suggestions for translating the findings into actual MIP development. KW - Anion receptors KW - Fluorescence sensing KW - Molecular dynamics simulations KW - Molecularly imprinted polymers KW - Rational design PY - 2018 DO - https://doi.org/10.1021/acs.langmuir.8b00500 SN - 0743-7463 VL - 34 IS - 23 SP - 6963 EP - 6975 PB - American Chemical Society CY - Washington, D.C. AN - OPUS4-45399 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sternbaek, L. A1 - Kimani, Martha Wamaitha A1 - Shinde, S. A1 - Alm, K. A1 - Sellegren, B. A1 - Gjörloff-Wingren, A. T1 - Macrophage-uptake of sialic acid-targeted molecularly imprinted polymers (SA-MIPs) N2 - Sialic acid (SA) is a cell surface glycan, which has a decisive role in many cell activities including differentiation, proliferation, and the immune response. The amount of SA has been found to correlate with cancer, with an upregulation on more aggressive cancers. Therefore, there is a great interest in developing methods for detection of SA on cancer cells. We are screening SA on cancer cell lines by using fluorescent molecularly imprinted polymers, SA-MIPs. Macrophages, which evolve from mono-cytes, are well known for their extraordinary ability to phagocytose foreign objects. This could lead to the hypothesis that the SA-MIPs can be recognized by macrophages as foreign object; thus leading to internalization and potentially degradation. We have demonstrated that SA-MIPs can be detected after incubation with the RAW macrophage cells, with increasing fluorescence over time. The microscopy analysis shows that the RAW cells ingest the SA-MIP particles. This information is important when planning to use SA-MIPs in future in vivo applications. T2 - 1st National Meeting of the Swedish Chemical Society CY - Lund University, Sweden DA - 17.06.2018 KW - Sialic acid KW - MIPs KW - Macrophages PY - 2018 AN - OPUS4-45421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sternbaek, L. A1 - Kimani, Martha Wamaitha A1 - Shinde, S. A1 - Alm, K. A1 - Sellegren, B. A1 - Gjörloff-Wingren, A. T1 - Macrophage-uptake of sialic acid-targeted molecularly imprinted polymers (SA-MIPs) N2 - Sialic acid (SA) is a cell surface glycan, which has a strong role in many cell activities including differentiation, proliferation, and the immune response. The amount of SA has been found to be correlated with cancer, with an upregulation on more aggressive cancers. Therefore, there is great interest in developing methods for detection of SA on cancer cells. We are screening SA on cancer cell lines by using fluorescent molecularly imprinted polymers, SA-MIPs.Macrophages, which evolve from mono-cytes, are well known for their extraordinary ability to phagocytose foreign objects. This could lead to the hypothesis that the SA-MIPs can be recognized by macrophages as foreign object; thus leading to internalization and potential degradation. We have discovered that SA-MIPs can be detected after incubation with the RAW macrophage cells, with increasing fluorescence over time. The microscopy analysis shows that the RAW cells ingest the SA-MIP particles. This information is important when planning to use SA-MIPs in future in vivo applications. T2 - The 69th Annual Conference of the Nordic Microscopy Society, 2018 CY - Lyngby, Denmark DA - 25.06.2018 KW - Sialic acid KW - MIPs KW - Macrophages PY - 2018 AN - OPUS4-45422 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ickert, Stefanie A1 - Hofmann, J. A1 - Riedel, Jens A1 - Beck, S. A1 - Pagel, K. A1 - Linscheid, M. W. T1 - Charge-induced geometrical reorganization of DNA oligonucleotides studied by tandem mass spectrometry and ion mobility N2 - Mass spectrometry is applied as a tool for the elucidation of molecular structures. This premises that gas-phase structures reflect the original geometry of the analytes, while it requires a thorough understanding and investigation of the forces controlling and affecting the gas-phase structures. However, only little is known about conformational changes of oligonucleotides in the gas phase. In this study, a series of multiply charged DNA oligonucleotides (n¼15–40) has been subjected to a comprehensive tandem mass spectrometric study to unravel transitions between different ionic gas-phase structures. The nucleobase sequence and the chain length were varied to gain insights into their influence on the geometrical oligonucleotide organization. Altogether, 23 oligonucleotides were analyzed using collision-induced fragmentation. All sequences showed comparable correlation regarding the characteristic collision energy. This value that is also a measure for stability, strongly correlates with the net charge density of the precursor ions. With decreasing charge of the oligonucleotides, an increase in the fragmentation energy was observed. At a distinct charge density, a deviation from linearity was observed for all studied species, indicating a structural reorganization. To corroborate the proposed geometrical change, collisional cross-sections of the oligonucleotides at different charge states were determined using ion mobility-mass spectrometry. The results clearly indicate that an increase in charge density and thus Coulomb repulsion results in the transition from a folded, compact form to elongated structures of the precursor ions. Our data show this structural transition to depend mainly on the charge density, whereas sequence and size do not have an influence. KW - Ion mobility KW - Collision-induced dissociation KW - Mass spectrometry KW - Oligonucleotide KW - Fragmentation KW - Tandem-MS PY - 2018 DO - https://doi.org/10.1177/1469066717746896 SN - 1469-0667 SN - 1751-6838 VL - 24 IS - 2 SP - 225 EP - 230 PB - Sage AN - OPUS4-44429 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ickert, Stefanie A1 - Riedel, Jens A1 - Beck, S. A1 - Linscheid, M. W. T1 - Negative nucleotide ions as sensitive probes for energy specificity in collision‐induced fragmentation in mass spectrometry N2 - Rationale: The most commonly used fragmentation methods in tandem mass spectrometry (MS/MS) are collision‐induced dissociation (CID) and higher energy collisional dissociation (HCD). While in CID the preselected ions in the trap are resonantly (and m/z exclusively) excited, in HCD the entire m/z range experiences the dissociative acceleration. The different excitation is reflected in different fragment distributions. Methods: As a test‐bed for particularly pronounced fragmentation specificity, here MS/MS experiments on several 4‐mer oligonucleotides were conducted employing both collision methods and the results were thoroughly compared. Oligonucleotides are shown to be sensitive probes to subtle changes, especially in the negative ion mode. A detailed analysis of these differences reveals insight into the dissociation mechanics. Results: Thedifferencesarerepresentedinheat‐maps,whichallowforadirectvisualinspection oflargeamountsofdata.Inthesefalsecolourrepresentationsthe,sometimessubtle,changesinthe individual dissociation product distributions become distinct. Another advantage of these graphic plots can be found in the formation of systematic patterns. These patterns reflect trends in dissociation specificity which allow for the formulation of general rules in fragmentation behavior. Conclusions: Instruments equipped with two different excitation schemes for MS/MS are today widely available. Nonetheless, direct comparisons between the individual results are scarcely made. Such comparative studies bear a powerful analytical potential to elucidate fragmentation reaction mechanism. KW - DNA KW - Tandem MS KW - HCD KW - CID PY - 2018 DO - https://doi.org/10.1002/rcm.8062 SN - 0951-4198 SN - 1097-0231 VL - 32 IS - 7 SP - 597 EP - 603 PB - Wiley & Sons, Ltd. AN - OPUS4-44430 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bell, Jérémy A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Die 3D-Mikrofluidik mit molekular geprägten Polymerpartikeln eröffnet neue Möglichkeiten der selektiven Pestizid-Bestimmung in Wasser N2 - 2,4-D ist ein in der Landwirtschaft weitverbreitetes Pflanzenschutzmittel, das Grundwasser kontaminiert, sich innerhalb der Nahrungskette anreichert und Umwelt- und Gesundheitsprobleme verursachen kann. Hier stellen die Autoren ein mikrofluidisches Nachweissystem für die Echtzeitdetektion von 2,4-D in Grund- oder Oberflächenwasser vor. Es basiert auf der Kombination 2,4-D-selektiver, fluoreszierender, molekular geprägter Polymer-(MIP-)Mikropartikel mit einem 3D-mikrofluidischen Extraktions- und Detektionssystem. Messungen vor Ort sollen damit künftig möglich sein. KW - 3D-Mikrofluidik KW - Sensorpartikel KW - MIP KW - Pestizid PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444781 UR - https://www.labo.de/epaper/LA0318/index.html SN - 0344-5208 IS - 3 SP - 10 EP - 13 PB - WEKA Business Medien GmbH AN - OPUS4-44478 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ickert, Stefanie A1 - Riedel, Jens A1 - Beck, S. A1 - Linscheid, M. W. T1 - Vacuum ultraviolet light as a new Tandem MS method N2 - Tandem MS techniques are widely used for both, structure and sequence elucidation of biopolymers. Thereby, fragmentation activation is realized by various methods, for example with lasers or collisions with neutral gases. In this study, we present a new Tandem MS system using a commercially available vacuum ultraviolet lamp. On the one hand, this approach provides efficient fragmentation in both ionization modes, positive as well as negative. On the other hand, it enables an additional previously not achieved post ionization of the fragments. While the first results in atypical fragment patterns and, thus provides orthogonal information, the second is crucial especially to identify low abundant ions. T2 - European Mass Spectrometry Conference CY - Saarbrücken, Germany DA - 10.03.2018 KW - Tandem MS KW - Vacuum Ultraviolet PY - 2018 AN - OPUS4-44484 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yuan, Huan A1 - Gornushkin, Igor B. A1 - Gojani, Ardian A1 - Wang, X. H. A1 - Rong, Ming Zhe T1 - Laser-induced plasma imaging for low-pressure detection N2 - A novel technique based on laser induced plasma imaging is proposed to measure residual pressure in sealed containers with transparent walls, e.g. high voltage vacuum interrupter in this paper. The images of plasma plumes induced on a copper target at pressure of ambient air between 10−2Pa and 105Pa were acquired at delay times of 200ns, 400ns, 600ns and 800ns. All the plasma images at specific pressures and delay times showed a good repeatability. It was found that ambient gas pressure significantly affects plasma shape, plasma integral intensities and expansion dynamics. A subsection characteristic method was proposed to extract pressure values from plasma images. The method employed three metrics for identification of high, intermediate and low pressures: the distance between the target and plume center, the integral intensity of the plume, and the lateral size of the plume, correspondingly. The accuracy of the method was estimated to be within 15% of nominal values in the entire pressure range between 10−2Pa and 105Pa. The pressure values can be easily extracted from plasma images in the whole pressure range, thus making laser induced plasma imaging a promising technique for gauge-free pressure detection. KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Plasma diagnostics PY - 2018 DO - https://doi.org/10.1364/OE.26.015962 SN - 1094-4087 VL - 26 IS - 12 SP - 15962 EP - 15971 PB - Optical Society of America under the terms of the OSA Open Access Publishing Agreement AN - OPUS4-45219 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kislenko, Evgeniia A1 - Wagner, Sabine A1 - Biyikal, Mustafa A1 - Rurack, Knut T1 - Molecularly Imprinted Polymers for Fluorescence Sensing of the Herbecide 2,4-D N2 - Application of pesticides is ubiquitous to better manage agricultural production. However, most of these compounds are harmful or toxic for humans and highly persistent in the environment, even in the crops themselves. Therefore, the rapid and reliable monitoring of pesticide residues is a very important area of environmental analysis. If conducted directly in the field, the use of fluorescence sensing methods is particularly attractive, because they allow for sensitive and rapid analyses while being very versatile. Recently, molecularly imprinted polymers (MIPs) have emerged as promising candidates for the primary sensing phase. Their robustness, low price and tunability render them an attractive alternative to more conventional biosensors based on antibodies. At present, a number of MIP formats are available besides the initial bulk polymer monoliths. Core/shell micro- and nanoparticles are especially suitable for sensor applications. A thin shell provides many advantages compared to a bulk polymer, such as fast diffusion of analyte, homogeneity of binding cavities and a higher number of binding sites closer to the surface. A strategy for sensory MIP synthesis is to introduce the fluorophore covalently into the polymer layer. The fluorescent probe monomer may thus consist of a fluorophore unit, a polymerizable unit and a recognition unit. One of the issues in targeting acidic pesticides such as 2,4-D is the fact that usually their deprotonated form is used for imprinting in organic solvents, commonly as the tetraalkylammonium salt. This approach harbours drawbacks when it comes to analytical rebinding, because real samples seldom contain such counterions. In our group, we have thus developed a new fluorescent probe monomer containing the 2-aminopyridine moiety, which forms strong enough intermolecular hydrogen bonds with the carboxylic acid group of neat 2,4-D. During a titration of the probe monomer with the analyte, hydrogen bond formation is indicated by spectral shifts and fluorescence enhancement. Crystallography studies verified complex formation. The higher fluorometric response of the core-shell MIP compared to a non-imprinted control polymer proved successful imprinting. Here, we will discuss the pros and cons of neutral molecule vs. salt imprinting, potentially expanding the possibilities of fluorescent sensory MIPs. T2 - MIP2018 CY - Hebrew University, Jerusalem, Israel DA - 24.06.2018 KW - Molecularly imprinted polymers KW - 2,4-D KW - Fluorescence KW - Sensing PY - 2018 AN - OPUS4-45598 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mansurova, Maria A1 - Bell, Jérémy A1 - Gotor, Raul A1 - Johann, Sergei A1 - Neumann, Patrick P. A1 - Kohlhoff, Harald A1 - Rurack, Knut T1 - Embedded Fluorescence-Based Optical System for the Detection of Total Petroleum Hydrocarbons in Water and Soil N2 - Contamination of natural bodies of water with oil and lubricants (or generally, hydrocarbon derivatives such as petrol, fuel and others) is a commonly found phenomenon around the world due to the extensive production, transfer and use of fossil fuels. In this work, we develop a simple system for the on-field detection of total petroleum hydrocarbons (TPH) in water and soil. The test is based on fluorescence emission of a 4-dimethylamino-4′-nitrostilbene derivative (4-DNS-OH). This fluorescent molecular rotor is embedded in a hydrophobic polymeric matrix (PVDF), avoiding interactions with water and providing a robust support for use in test-strip fashion. For the fluorescence detection a portable sensor device was developed, featuring two excitation LEDs, a micro-spectrometer and Bluetooth control. A limit of detection of at least 6 ppm of TPH in water was demonstrated. T2 - Europtrode 2018 CY - Naples, Italy DA - 25.03.2018 KW - Water KW - Fluorescence KW - Spectrocube KW - Rapid test KW - Oil PY - 2018 AN - OPUS4-45605 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mansurova, Maria A1 - Bell, Jérémy A1 - Gotor, Raul A1 - Rurack, Knut T1 - Fluorescence-based optical system for the detection of total petroleum hydrocarbons in water and soil with smartphone read-out compatibility - Spectrocube, a sensor for rapid oil test in water and soil N2 - Contamination of natural bodies of water with oil and lubricants (or generally, hydrocarbon derivatives such as petrol, fuel and others) is a commonly found phenomenon around the world due to the extensive production, transfer and use of fossil fuels. The timely identification of these contaminants is of utmost importance, since they directly affect water quality and represent a risk for wildlife and human health even in trace amounts. In this work, we develop a simple system for the on-field detection of total petroleum hydrocarbons (TPH) in water and soil, the "Spectrocube". The test is based on the measurement of the fluorescence signal emitted by the molecular rotor 4-DNS-OH dye. This dye is embedded in a hydrophobic polymeric matrix (PVDF), avoiding interactions of water with the dye and providing a robust support for use in test-strip fashion. The test-strip’s fluorescence intensity increases linearly at low concentrations of TPH, reaching a saturation value at higher concentrations. For excitation and evaluation of the test-strip fluorescence, a simple miniature optical system was designed. The system works semi-quantitatively as solvent-free TPH detection kit, as well as quantitatively when using a simple cyclopentane extraction step. To simplify the fluorescence read-out, the device is coupled to a tablet computer via Bluetooth, running a self-programmed software ("app"). T2 - Oil Spill India 2018 CY - New Delhi, India DA - 05.07.2018 KW - Oil analysis KW - Water analysis KW - Fluorescence KW - Spectrocube KW - Rapid test KW - Field test KW - Spectroscopy KW - Sensor PY - 2018 AN - OPUS4-45606 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tobias, Charlie A1 - Climent Terol, Estela A1 - Hodoroaba, Vasile-Dan A1 - Rurack, Knut T1 - Design, Synthesis and Application of Polymer Core/Mesoporous Silica Shell Particles as Promising Tools for Multiplexed Assays N2 - The simultaneous detection of different analytes has gained increasing importance in recent years, especially in the fields of environmental and health monitoring. Particularly suitable formats for multiplexing are bead-based assays. The beads employed need to fulfil size and density requirements important for instance for flow cytometry and shall exhibit an as high as possible surface area for anchoring capture probes to allow for low limits of detection. Core/shell particles are ideally suited in this sense because of their modularity in design and adaptability for various (bio)analytical assays. Here, polystyrene particles coated with different kinds of mesoporous silica shells are presented, possessing distinctly higher surface areas in comparison to non-porous core/shell particles. Different factors such as pH and amount and type of mediator salt used during shell preparation were evaluated with shell inspection by scanning/transmission scanning electron microscopy (SEM/tSEM) being key to architecture control of the monodisperse particles. For a cytometric model assay, the optimized core/shell particles were functionalized with capture oligonucleotides for DNA detection. After covalent attachment of single-stranded DNA to the silane-modified silica surface, a hybridisation assay using labelled t-DNA complementary strands was carried out to demonstrate particle performance, showing how tailoring of the shell’s surface area controls sensitivity and dynamic range of the assay. Finally, a multiplex assay for the determination of DNA from different human papilloma virus (HPV) lines was developed. Using our optimized particles, we were able to detect down to 10 amolμl‒1, which is an improvement of one order of magnitude compared to assays using non-porous particles reported in the literature. In addition, multiplexed detection could successfully be demonstrated. T2 - ANAKON 2019 CY - Münster, Germany DA - 25.03.2019 KW - Core−shell particles KW - Bead-based assay KW - Flow cytometry KW - Multiplex PY - 2019 AN - OPUS4-48082 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Laser induced Plasma: Modeling and diagnostics N2 - Laser-induced plasmas are widely used in many areas of science and technology; examples include spectrochemical analysis, thin film deposition, material processing, and even jet propulsion. Several topics will be addressed. First, general phenomenology of laser-induced plasmas will be discussed. Then, a chemical model will be presented based on a coupled solution of Navier-Stokes, state, radiative transfer, material transport, and chemical (Guldberg-Waage) equations. Results of computer simulations for several chemical systems will be shown and compared to experimental observations obtained by optical imaging, spectroscopy, and tomography. The latter diagnostic tools will also be briefly discussed. T2 - Lecture at the Dept of Chemistry of Czeged University (Hungary) on 31.05.2019 CY - Czeged, Hungary DA - 31.05.2019 KW - Plasma KW - LIBS KW - Plasma modeling PY - 2019 AN - OPUS4-48188 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Several approaches to calibration-free LIBS: Advantages and pitfalls N2 - An overview of calibration-free laser induced breakdown spectroscopy (CF LIBS) methods is presented. Advantages and pitfalls of these methods are critically discussed. T2 - Workshop of the Spectrochemical Working Committee (SWC) of the Hungarian Academy of Sciences CY - Budapest, Hungary DA - 05.06.2019 KW - Calibration-free LIBS KW - CF LIBS algorithms PY - 2019 AN - OPUS4-48189 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bell, Jérémy A1 - Tillo, Adam A1 - Chauhan, Vraj P. A1 - Bartelmeß, Jürgen A1 - Rurack, Knut T1 - Microfluidic analytical tool coupling a fluorescent molecular probe and a micro-hydrocyclone for the detection of water chlorination level N2 - Chlorination of pool water and wastewater, in food and pharmaceutical production, as well as in pesticide and paper manufacturing is a routinely used technique. However, the amount of chlorine in water must be strictly adjusted, to ensure enough concentration to kill pathogenic bacteria and viruses, while preventing too high concentrations inducing negative effects on human health. As an indicator, a molecular fluorescent probe based on a BODIPY structure was designed. This indicator exhibits a sensitive and selective fluorescence response upon increasing concentrations of hypochlorite in aqueous solvent mixtures. Real-time analyses became possible after the integration of this fluorescent indicator into newly designed 2D & 3D microfluidic chips incorporating a passive sinusoidal mixer and a micro-hydrocyclone, respectively. A comparison of the two microfluidic systems, including their ability to prevent accumulation or circulation of microbubbles, has shown excellent fluidic behaviour for the micro-hydrocyclone device. This system was distinctly more robust against gas bubbles, showed a higher signal gain and allowed to halve the limit of detection to 0.02 mg L–1. The use of the 3D system to quantify the chlorine content of pool water samples for sensitive and quantitative chlorine monitoring has been demonstrated. T2 - Konferenz CY - Ioannina, Greece DA - 22.09.2019 KW - Chlorine KW - Fluorescence KW - Microfluidics KW - Water KW - Chlor KW - Fluoreszenz KW - Mikrofluidik KW - Wasser PY - 2019 UR - https://media.conferre.gr/index.php/photos-videos/ima2019 AN - OPUS4-49130 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Képeš, E. A1 - Gornushkin, Igor B. A1 - Pořízka, P. A1 - Kaiser, J. T1 - Tomography of double-pulse laser-induced plasmas in the orthogonal geometry N2 - The temporal evolution of laser-induced plasmas is studied in the orthogonal double-pulse arrangement. Both the pre-ablation mode (an air spark is induced above the sample surface prior to the ablation pulse) and the re-heating mode (additional energy is delivered into the plasma created by the ablation pulse) is considered. The plasmas are investigated in terms of the temporal evolution of their electron density, temperature, and volume. The plasma volumes are determined using a time-resolved tomography technique based on the Radon transformation. The reconstruction is carried out for both white-light and band-pass filtered emissivities. The white-light reconstruction corresponds to the overall size of the plasmas. On the other hand, the band-pass emissivity reconstruction shows the distribution of the atomic sample species (Cu I). Moreover, through spectrally resolved tomographic reconstruction, the spatial homogeneity of the electron density and temperature of the plasmas is also investigated at various horizontal slices of the plasmas. Our results show that the pre-ablation geometry yields a more temporally stable and spatially uniform plasma, which could be beneficial for calibration-free laser-induced breakdown spectroscopy (LIBS) approaches. On the contrary, the plasma generated in the re-heating geometry exhibits significant variations in electron density and temperature along its vertical axis. Overall, our results shed further light on the mechanisms involved in the LIBS signal enhancement using double-pulse ablation. KW - Laser-induced plasma KW - Laser-induced breakdown spectroscopy KW - Double-pulse laserinduced breakdown spectroscopy KW - Plasma tomography KW - Radon reconstruction PY - 2020 DO - https://doi.org/10.1016/j.aca.2020.06.078 SN - 0003-2670 SN - 0378-4304 VL - 1135 SP - 1 EP - 11 PB - Elsevier CY - Amsterdam AN - OPUS4-51142 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Qiu, Yan A1 - Yu, H. A1 - Gornushkin, Igor B. A1 - Li, J. A1 - Wu, Q. A1 - Zhang, Z. A1 - Li, X. T1 - Measurement of trace chromium on structural steel surface from a nuclear power plant using dual-pulse fiber-optic laser-induced breakdown spectroscopy N2 - Remote and on-line measurement of chromium on structural steel surface in nuclear power plants is critical for protection against fluid accelerated corrosion. To improve the insufficient sensitivity of fiber-optic laser-induced breakdown spectroscopy toward trace element detection, a dual-pulse spectral enhancement system is set up. In an iron matrix, for the purpose of improving sensitivity of trace chromium analysis and reducing the self-absorption of iron, the effects of key parameters are investigated. The optimal values of the parameters are found to be: 450 ns inter-pulse delay, 700 ns gate delay, 30 mJ/6 mJ pulse energy ratio, and 19.8 mm lens-to-sample distance (corresponding to a 799 μm laser focused spot size). Compared to the single-pulse system, the shot number of dual-pulse ablation is limited for reducing surface damage. After the optimization of the dual-pulse system, the signal-to-noise ratio of the trace chromium emission line has been improved by 3.5 times in comparison with the single-pulse system, and the self-absorption coefficient of matrix iron has been significantly reduced with self-reversal eliminated. The number of detectable lines for trace elements has more than doubled thus increasing the input for spectral calibration without significantly increasing the ablation mass. Three calibration methods including internal standardization, partial least squares regression and random forest regression are employed to determine the chromium and manganese concentrations in standard samples of low alloy steel, and the limit of detection is respectively calculated as 36 and 515 ppm. The leave-one-out cross validation method is utilized to evaluate the accuracy of chromium quantification, and the concentration mapping of chromium is performed on the surface of a steel sample (16MND5) with a relative error of 0.02 wt.% KW - Fiber-optic laser-induced breakdown spectroscopy (FO-LIBS) KW - Dual-pulse KW - Parameter optimization KW - Spectral enhancement KW - Self-absorption coefficient KW - Concentration mapping PY - 2020 DO - https://doi.org/10.1016/j.apsusc.2020.147497 SN - 0169-4332 VL - 533 IS - 147497 SP - 1 EP - 29 PB - Elsevier CY - Amsterdam AN - OPUS4-51143 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Sennikov, P. G. A1 - Kornev, R. A. A1 - Polyakov, V. S. T1 - Equilibrium calculations for plasmas of volatile halides of III, IV and VI group elements mixed with H2 and H2 + CX4 (X = H, Cl, F) relevant to PECVD of isotopic materials N2 - The composition of hydrogen and hydrogen-methane plasmas containing ~10% of BX₃, SiX₄, GeX₄ (X = F, Cl), SF₆, MoF₆ and WF₆ is calculated for the temperature range ~300-4000 K using the equilibrium chemical model. The calculations provide valuable information about thermodynamic parameters (pressure, temperature) needed for condensation of pure elements (in H₂ plasma) and their carbides (in H₂ + CH₄ plasma) and about intermediate reaction products. Using volatile fluorides for plasma chemical deposition alleviates obtaining monoisotopic elements and their isotopic compounds because fluorine is monoisotopic. PECVD is promising method for one-step conversion of fluorides to elemental isotopes and their carbides. For fluorides, further insight is needed into properties of plasmas supported by different types of discharges. KW - Plasma chemistry KW - Modeling chemical reactions KW - Plasma enhanced chemical vapor deposition KW - Reduction of volatile chlorides and fluorides by hydrogen PY - 2020 DO - https://doi.org/10.1007/s10967-020-07295-2 VL - 326 IS - 1 SP - 407 EP - 421 PB - Springer CY - Dordrecht AN - OPUS4-51144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Sennikov, P. A1 - Kornev, R. A1 - Ermakov, A. A1 - Shkrunin, V. T1 - Laser Induced Dielectric Breakdown for Chemical Vapor Deposition by Hydrogen Reduction of Volatile Boron Halides BCl3 and  BF3 N2 - A possibility of deposition from laser-induced plasma is investigated in search for an economic and simple method for obtaining isotopic compounds from enriched gaseous precursors although no isotopic compounds are used in this the proof-of-principle work. A breakdown in mixtures of BCl3 and BCl3 with hydrogen, argon, and methane are studied both theoretically and experimentally. Equilibrium chemistry calculations show the deposition of boron, boron carbide, and carbon is thermodynamically favorable in BCl3 systems and only carbon in BF3 systems. Dynamic calculation of expanding plasma is performed using fluid dynamics coupled with equilibrium chemistry. Condensed phases of boron, boron carbide, and graphite are predicted with maximum concentrations in peripheral zones of the plasma. In experiment, plasma is induced in mixtures BCl3, H2 + BCl3, H2 + Ar + BCl3, H2 + BCl3 + CH4, BF3, H2 + BF3, H2 + Ar + BF3, and H2 + Ar + BF3. The gases are analyzed before, during, and after laser irradiation by optical and mass spectrometry methods. The results show the composition of reaction products close to that predicted theoretically. The conversion of precursor gases BCl3 and BF3 into gaseous and condensed products is 100% for BCl3 and 80% for BF3. Solid deposits of up to 30 mg are obtained from all reaction mixtures. Due to technical reasons only FTIR characterization of the BCl3 + H2 + CH4 deposit is done. It points to presence of condensed boron and boron carbide predicted by the model. Overall, the calculations and preliminary experimental results imply the chemical vapor deposition with laser induced plasma is promising for conversion of gaseous enriched precursors into elemental isotopes and their isotopic compounds. KW - Boron halides KW - Chemical vapor deposition KW - Laser induced dielectric breakdown, Hydrogen reduction PY - 2020 DO - https://doi.org/10.1007/s11090-020-10096-w VL - 40 IS - 5 SP - 1145 EP - 1162 PB - Springer AN - OPUS4-50968 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Li, Q. A1 - Shinde, S. A1 - Grasso, G. A1 - Caroli, A. A1 - Abouhany, R. A1 - Lanzillotta, M. A1 - Pan, G. A1 - Wan, Wei A1 - Rurack, Knut A1 - Sellergren, B. T1 - Selective detection of phospholipids using molecularly imprinted fluorescent sensory core-shell particles N2 - Sphingosine-1-phosphate (S1P) is a bioactive sphingo-lipid with a broad range of activities coupled to its role in G-protein coupled receptor signalling. Monitoring of both intra and extra cellular levels of this lipid is challenging due to its low abundance and lack of robust affinity assays or sensors. We here report on fluorescent sensory core-shell molecularly imprinted polymer (MIP) particles responsive to near physiologically relevant levels of S1P and the S1P receptor modulator fingolimod phosphate (FP) in spiked human serum samples. Imprinting was achieved using the tetrabutylammonium (TBA) salt of FP or phosphatidic acid (DPPA·Na) as templates in combination with a polymerizable nitrobenzoxadiazole (NBD)-urea monomer with the dual role of capturing the phospho-anion and signalling its presence. The monomers were grafted from ca 300 nm RAFT-modified silica core particles using ethyleneglycol dimethacrylate (EGDMA) as crosslinker resulting in 10–20 nm thick shells displaying selective fluorescence response to the targeted lipids S1P and DPPA in aqueous buffered media. Potential use of the sensory particles for monitoring S1P in serum was demonstrated on spiked serum samples, proving a linear range of 18–60 μM and a detection limit of 5.6 μM, a value in the same range as the plasma concentration of the biomarker. KW - Molecularly imprinted polymers KW - Phospholipids KW - Fluorescence KW - Dye monomers PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509485 DO - https://doi.org/10.1038/s41598-020-66802-3 SN - 2045-2322 VL - 10 IS - 1 SP - 9924 PB - Nature Research CY - London AN - OPUS4-50948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Climent Terol, Estela T1 - Design and synthesis of lateral flow tests containing antibody-gated materials N2 - Methods for the rapid and sensitive detection of target analytes are gaining importance in medical diagnostics and environmental monitoring, in the security, occupational health and safety as well as food sectors. Among all the methods employed for rapid tests, lateral flow assays (LFAs) are the most commonly used. However, some drawbacks are that most of these tests either indicate the analyte only indirectly, and in other cases the sensitivity is not high enough. Keeping in mind these limitations, the use of stimuli-responsive materials for small-molecule sensing relying on chemical signal amplification and utilizing specific interactions between biomolecules such as antibodies and the corresponding analytes are particularly attractive. Such materials can also be incorporated on paper strips for lateral-flow assays in a straightforward manner. These sensing materials comprise mesoporous silica nanoparticles loaded with indicator molecules and containing certain hapten derivative molecules covalently grafted at the surface, which bind to the respective antibody and inhibit the release of a dye as reporter (Scheme 1). In presence of the designated analyte, a displacement of the antibody from the material is observed, allowing the release of dye. Because a large number of indicator molecules can be released when a single analyte molecule binds to an antibody cap, a strong signal amplification is observed. Considering the modularity, high sensitivity and selectivity of these antibody-gated indicator delivery systems, the presentation discusses general aspects of system design as well as analytical performance and highlights the integration into a lateral-flow assay, showing as an example the determination of the explosives TATP, TNT and PETN with a fluorescence readout, in single-substance and multiplexing modes. T2 - International Webinar on Biosensors and Bioelectronics CY - Online meeting DA - 20.07.2020 KW - Multiplexing detection KW - Rapid testing methods KW - Gated hybrid materials KW - Lateral flow tests KW - Explosives detection PY - 2020 UR - https://europeanmeetings.net/conferences/biosensor-bioelectronics AN - OPUS4-51038 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. A1 - Sennikov, P. A1 - Kornev, R. A1 - Ermakov, A. A1 - Shkrunin, V. T1 - Laser Induced Plasma for Chemical Vapor Deposition: Theory and Experiment N2 - A possibility of deposition from laser-induced plasma (LIP) is investigated in search for an economic and simple method to obtain isotopic compounds from enriched gaseous precursors. A breakdown in mixtures of BCl3 and BCl3 with hydrogen, argon, and methane are studied both theoretically and experimentally. Calculations of expanding plasma of different composition are performed with the use of the fluid dynamic code coupled to the equilibrium chemistry solver. Condensed phases of boron, boron carbide, and graphite are predicted showing maximum concentrations in peripheral zones of the plasma. In experiment LIP is induced in mixtures BCl3, Н2+BCl3, H2+Ar+BCl3, H2+BCl3+CH4, BF3, Н2+BF3, H2+Ar+BF3, and H2+Ar+BF3. The gases are analyzed before, during, and after laser irradiation by optical and mass spectroscopic methods. The composition of reaction products is found to be close to that predicted theoretically. The conversion of precursor gases BCl3 and BF3 into gaseous and condensed products is 100% for BCl3 and 80% for BF3. Solid deposits of up to 30 mg are obtained from all the reaction mixtures. FTIR analysis of BCl3+H2+CH4 deposits points to a presence of condensed boron and boron carbide that are also predicted by the model. Both calculations and preliminary experimental results suggest the chemical vapor deposition by LIP is promising for conversion of gaseous enriched precursors into elemental isotopes and their isotopic compounds. T2 - International Online Meeting on Laser Induced Breakdown Spectroscopy (IIOMLIBS) CY - Online meeting DA - 06.07.2020 KW - Chemical vapor deposition KW - Laser induced plasma PY - 2020 AN - OPUS4-50994 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krahl, T. A1 - Beer, F. A1 - Relling, A. A1 - Gawlitza, Kornelia A1 - Rurack, Knut A1 - Kemnitz, E. T1 - Toward Luminescent Composites by Phase Transfer of SrF2 :Eu3+ Nanoparticles Capped with Hydrophobic Antenna Ligands N2 - Transparent dispersions of hydrophobic SrF2 :Eu3+ nanoparticles in cyclohexane with up to 20% europium were obtained by fluorolytic sol-gel synthesis followed by Phase transfer into cyclohexane through capping with sodium dodecylbenzenesulfonate (SDBS). The particles were characterized by TEM, XRD and DLS as spherical objects with a diameter between 6 and 11 nm in dry state. 1H-13CP MAS NMR experiments revealed the binding of the anionic sulfonate head group to the particle surface. The particles show bright red luminescence upon excitation of the aromatic capping agents, acting as antennas for an Energy transfer from the benzenesulfonate unit to the Eu3+ centers in the particles. This synthesis method overcomes the current obstacle of the fluorolytic sol-gel synthesis that transparent dispersions can be obtained directly only in hydrophilic solvents. To demonstrate the potential of such hydrophobized alkaline-earth fluoride particles, transparent luminescent organic-inorganic composites with 10% SrF2 :Eu3+ embedded into polyTEGDMA, polyBMA, poly-BDDMA and polyD3MA, respectively, were prepared, endowing the polymers with the luminescence features of the nanoparticles. KW - Nanoparticles KW - Fluorides KW - Sol-gel process KW - Organic-inorganic hybrid composites PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508668 DO - https://doi.org/10.1002/cnma.202000058 SP - 1 EP - 11 PB - Wiley AN - OPUS4-50866 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gawlitza, Kornelia A1 - Johann, Sergej A1 - Mansurova, M. A1 - Kohlhoff, Harald A1 - Tiebe, Carlo A1 - Bell, Jérémy A1 - Bartholmai, Matthias A1 - Rurack, Knut T1 - Semi-automatic Measurement Device for Long-Term Monitoring of Ammonia in Gas Phase N2 - The present paper describes the development of a sensor material that changes its fluorescence in the presence of gaseous ammonia in a relevant concentration range. The implementation into a semi-automatic gas measurement device enables low-cost, precise, simple and fast monitoring of low con-centrations of harmful gases, like ammonia, and hence can help to improve the climate monitoring in livestock housing, barns or stables. T2 - SMSI 2020 CY - Meeting was canceled KW - Spectroscopy KW - Emmbedded sensor KW - Environment KW - Air quality PY - 2020 DO - https://doi.org/10.5162/SMSI2020/B5.4 SP - 133 EP - 134 AN - OPUS4-50867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kimani, Martha Wamaitha A1 - Kislenko, Evgeniia A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Design, Synthesis and Characterization of Fluorescent MIP Particles for Labelling of Malignant Cells N2 - Cancer is a leading cause of death worldwide, and its early detection and resultant treatment contributes significantly to patient recovery and survival. Detection is currently based on magnetic resonance imaging and computed tomography, methods that are expensive, while processing of the results is time-consuming1. There is a need for low-cost cancer detection techniques that give conclusive results in the shortest time possible. When equipped with a reporter function, molecularly imprinted polymers (MIPs) targeting tumor markers on cancerous cells may provide a cheaper solution for imaging-based cancer detection. Thin MIP layers immobilized on particle platforms are ideal in this regard, because a fluorescence reporter can be integrated into the particle core and/or MIP shell and such core/shell nanoparticles show faster response times and increased selectivity in comparison to bulk MIPs. Changes in sialylation patterns of cell surface glycans indicate malignancy2. Here, we present the design, synthesis and characterization of MIPs that target sialic acid-terminated glycans (SA MIPs), prepared as a thin layer on a polystyrene core/silica shell nanoparticle platform. The MIP particles contain fluorescent emitters and can be applied in fluorescence imaging of malignant tumors. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) are used for structural characterization. Binding capacity of the MIPs to target glycans and competing sugars is also evaluated and compared to that of the corresponding non-imprinted polymer particles (NIP). T2 - Mini MIP Conference CY - Online meeting DA - 16.06.2020 KW - Cancer KW - MIPs KW - Sialic acid PY - 2020 AN - OPUS4-50901 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bell, Jérémy A1 - Biyikal, Mustafa A1 - Rurack, Knut T1 - Embedded sensor based on tandem smartphone-microfluidic device for the detection of TNT in surface and sea waters N2 - The globe's seas were used as dumping ground after the world wars and those millions of ammunition, most of all containing 2,4,6-trinitrotoluene (TNT), represent a pressing danger for fishermen, dredging operations, submarine cable installations and tourism. We developed an extremely selective indication method for TNT based on a specific reaction that produces a highly fluorescent compound. The indication system was integrated into a microfluidic PDMS chip for the solid-liquid extraction of TNT from water samples, offering environmental monitoring possibilities. Combining the advantages of a light-up indicator, microfluidics and a smartphone as detector, the embedded sensor allows for the remote and rapid detection of TNT down to ng in surface and sea waters. T2 - µTAS 2020 CY - Online meeting DA - 05.10.2020 KW - Smartphone KW - Rapid test KW - TNT KW - Ammunition KW - Schnelltest KW - Munition PY - 2020 AN - OPUS4-51444 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gaft, M. A1 - Nagli, L. A1 - Gornushkin, Igor B. A1 - Raichlin, Y. T1 - Review on recent advances in analytical applications of molecular emission and modelling N2 - The review mainly deals with two topics that became important in applications of laser-induced breakdown spectroscopy (LIBS) in recent years: the emission of halogen- and rare-earth-containing molecules and selective excitation of molecules by molecular laser-induced fluorescence (MLIF). The first topic is related to the emission of alkaline-earth diatomic halides MX, M = Ca, Mg, Ba, Sr and X = F, Cl, Br, and I and rare-earth element (REE) oxides LaO, YO, and ScO. These molecules form in laser-induced plasma (LIP) soon after its ignition and persist for a long time, emitting broad bands in a visible part of the spectrum. They are best detected after relatively long delay times when emission from interfering plasma species (atoms and ions) has already been quenched. Such behavior of molecular spectra allows of using, for their detection, inexpensive CCD detectors equipped with simple electronic or mechanical shutters and low-resolution spectrometers. A main target for analysis by molecular spectroscopy is halogens; these elements are difficult to detect by atomic spectroscopy because their most intense atomic lines lie in the vacuum UV. Therefore, in many situations, emission from CaF and CaCl may provide a substantially more sensitive detection of F and Cl than emission from elemental F and Cl and their ions. This proved to be important in mining and concrete industries and even Mars exploration. A similar situation is observed for REEs; their detection by atomic spectroscopy sometimes fails even despite the abundance of atomic and ionic REEs' lines in the UV-VIS. For example, in minerals and rocks with low concentrations of REEs, emission from major and minor mineral elements hinders the weak emission from REEs. Many REEs do not form molecules that show strong emission bands in LIP but can still be detected with the aid of LIP. All REEs except La, Y, and Sc exhibit long-lived luminescence in solid matrices that is easily excited by LIP. The luminescence can be detected simultaneously with molecular emission of species in LIP within the same time and spectral window. The second topic is related to the combination of MLIF and LIBS, which is a technique that was proved to be efficient for analysis of isotopic molecules in LIP. For example, the characteristic spectral signals from isotopic molecules containing 10B and 11B are easier to detect with MLIF-LIBS than with laser ablation molecular isotopic spectrometry (LAMIS) because MLIF provides strong resonance excitation of only targeted isotopes. The technique is also very efficient in detection of halogen molecules although it requires an additional tunable laser that makes the experimental setup bulky and more expensive. KW - Plasma induced luminescence KW - Molecular emission KW - Laser induced plasma KW - Plasma modeling KW - Molecular analysis KW - LIBS PY - 2020 DO - https://doi.org/10.1016/j.sab.2020.105989 VL - 173 SP - 105989 PB - Elsevier B. V. AN - OPUS4-51420 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kislenko, Evgeniia A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Fluorescent molecularly imprinted polymers (MIPs) for sensing of phosphorylated protein epitopes N2 - Early detection of cancer is instrumental for successful therapeutic outcomes, but it is presently a considerable challenge. Biopsy of potentially cancerous tissues is the gold standard in medicine for the diagnosis and prognosis of this disease; however, it may not be possible in many cases due to tumour position or other complications. Liquid biopsy-based detection of specific cancer markers in biological fluids can be easily performed via immunoanalytical techniques. However, antibody-based methods suffer from high cost of tumour specific antibodies due to difficult and lengthy production. Furthermore, antibodies may have limited specificity to the target molecule, and limited lifetimes. The so-called “plastic antibodies” as MIPs can be a more affordable, reliable and stable alternative to antibodies, especially for cancer diagnostics. Our goal is to create MIP particles to selectively bind cancer biomarkers and rapidly display a fluorescence change upon interaction with molecules of interest. Epitopes containing the phosphorylated tyrosine (pY) motif such as tripeptide YpYG and tetrapeptide pYEEI were selected as target analytes. Cancers may disrupt tyrosine phosphorylation processes regulated by human tyrosine kinases such as ZAP-70 and subsequently lead to a pronounced increase in pY residues on proteins. To ensure fast diffusion of analyte and rapid response core/shell silica micro- and nanoparticles with a thin polymer shell was chosen as the format for MIP synthesis. Fluorescent probe monomers consisting of fluorophore and recognition units are directly integrated in the polymer shell to obtain fluorescence response upon analyte binding. We have synthesized the fluorescent MIP particles based on the previously published report [W. Wan et al., Chem. Eur. J., 2017, 23, 15974-1598] for the novel phosphorylated targets with a high imprinting factor and high degree of discrimination between target analyte and non-phosphorylated and smaller competitors. The synthesized particles may be used in microfluidic devices for the rapid diagnostics of cancer. T2 - GSSMIP2019 CY - Berlin, Germany DA - 28.08.2019 KW - Analytical Sciences KW - Sensorik PY - 2019 AN - OPUS4-50227 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kislenko, Evgeniia A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Fluorescent molecularly imprinted polymers (MIPs) for sensing of phosphorylated protein epitopes N2 - Early detection of cancer is instrumental for successful therapeutic outcomes, but it is presently a considerable challenge. Biopsy of potentially cancerous tissues is the gold standard in medicine for the diagnosis and prognosis of this disease; however, it may not be possible in many cases due to tumour position or other complications. Liquid biopsy-based detection of specific cancer markers in biological fluids can be easily performed via immunoanalytical techniques. However, antibody-based methods suffer from high cost of tumour specific antibodies due to difficult and lengthy production. Furthermore, antibodies may have limited specificity to the target molecule, and limited lifetimes. The so-called “plastic antibodies” as MIPs can be a more affordable, reliable and stable alternative to antibodies, especially for cancer diagnostics. Our goal is to create MIP particles to selectively bind cancer biomarkers and rapidly display a fluorescence change upon interaction with molecules of interest. Epitopes containing the phosphorylated tyrosine (pY) motif such as tripeptide YpYG and tetrapeptide pYEEI were selected as target analytes. Cancers may disrupt tyrosine phosphorylation processes regulated by human tyrosine kinases such as ZAP-70 and subsequently lead to a pronounced increase in pY residues on proteins. To ensure fast diffusion of analyte and rapid response core/shell silica micro- and nanoparticles with a thin polymer shell was chosen as the format for MIP synthesis. Fluorescent probe monomers consisting of fluorophore and recognition units are directly integrated in the polymer shell to obtain fluorescence response upon analyte binding. We have synthesized the fluorescent MIP particles based on the previously published report for the novel phosphorylated targets with a high imprinting factor and high degree of discrimination between target analyte and non-phosphorylated and smaller competitors. The synthesized particles may be used in microfluidic devices for the rapid diagnostics of cancer. T2 - GSSMIP2019 CY - Berlin, Deutschland DA - 28.08.2019 KW - Analytical Sciences KW - Sensorik PY - 2019 AN - OPUS4-50228 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gojani, Ardian A1 - Palásti, David J. A1 - Paul, Andrea A1 - Galbacs, G. A1 - Gornushkin, Igor B. T1 - Application of spatial heterodyne spectroscopy for chemical analysis based on Raman and laser-induced breakdown spectroscopy N2 - Spatial Heterodyne Spectroscopy (SHS) is a spectrometric technique that combines both dispersive and interferometric features into a customizable instrument. The Basis of SHS is a Michelson interferometer with its mirrors replaced by diffraction gratings and with no moving parts. The output signal from SHS is the interferogram, which is recorded with a 1D or 2D pixel array detector. The spatial periodicity of the fringes on the interferogram is a function of the wavelength of the diffracted light. Using the Fast Fourier Transform, the original optical spectrum that enters SHS is retrieved. The light that is analyzed by SHS can come from a variety of sources. In our work, we used Raman scattering and Laser-Induced Plasma to perform quantitative and qualitative analyses. Figure 1 compares the performance of the SHS with that of high Resolution echelle and portable low-resolution asymmetrically crossed Czerny-Turner spectrometers (OO in Fig.1). The analyzed light came from the plasma induced on a stainless-steel reference material. The SHS exhibits the resolution comparable to that of the echelle spectrometer used, about 8000. Due to a high throughput of the SHS (theoretically, ~200 times higher than that of grating instruments), the number of spectra needed to be accumulated for comparable signal-to-noise ratios is much smaller than in the case of the echelle and comparable to OO spectrometers. Examples of Raman SHS applied to several pure liquids are given in Fig. 2. Raman SHS was used in three different settings: (i) for classification of six types of oils, (ii) for univariate/multivariate analysis of binary mixture cyclohexane-isopropanol, and (iii) for multivariate analysis of glycerol solution in water. For the last two settings, chemometric analysis of the spectra yielded linear calibration plots over the range 1-90% of concentrations of isopropanol in cyclohexane, and 0.5-10% of glycerol in water. T2 - ANAKON 2019 CY - Münster, Germany DA - 25.03.2019 KW - Spatial heterodyne spectroscopy KW - Raman spectroscopy KW - Laser-Induced Background Spectroscopy PY - 2019 AN - OPUS4-49176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bartelmeß, Jürgen A1 - Valderrey, Virginia A1 - Rurack, Knut T1 - Development of a “Turn-on” Fluorescent Probe-Based Sensing System for Hydrogen Sulfide in Liquid and Gas Phase N2 - A “turn-on” fluorescence sensing system based on a BODIPY-cobaloxime complex for the detection of H2S in liquid and gas phase was developed. To that aim, two cobaloxime complexes bearing an axial pyridyl-BODIPY ligand were initially evaluated as sensitive fluorescent HS− indicators in aqueous solution. The sensing mechanism involves the selective substitution of the BODIPY ligand by the HS− anion at the cobalt center, which is accompanied by a strong fluorescence enhancement. The selection of a complex with an ideal stability and reactivity profile toward HS− relied on the optimal interaction between the cobalt metal-center and two different pyridyl BODIPY ligands. Loading the best performing BODIPY-cobaloxime complex onto a polymeric hydrogel membrane allowed us to study the selectivity of the probe for HS− against different anions and cysteine. Successful detection of H2S by the fluorescent “light-up” membrane was not only accomplished for surface water but could also be demonstrated for relevant H2S concentrations in gas phase. KW - Sulfide sensing KW - Fluorescence KW - BODIPYs KW - Cobaloxime complex KW - Gas sensing PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492186 DO - https://doi.org/10.3389/fchem.2019.00641 SN - 2296-2646 VL - 7 SP - Art. Nr. 641 PB - Frontiers Media CY - Lausanne AN - OPUS4-49218 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Xue, Boyang A1 - Riedel, Jens A1 - Gornushkin, Igor B. A1 - Zheng, R. A1 - You, Yi T1 - High-throughput underwater elemental analysis through optical emission spectroscopy with ultrasound-assisted μJ-laser-induced breakdown at kHz repetition rate N2 - The elemental analysis of seawater is often critical to the understanding of marine chemistry, marine geochemistry, and the deep-sea ecosystems. Laser-induced breakdown spectroscopy (LIBS) with the advantage of rapid multi-elements detection, has a great potential for in-situ elemental analysis of seawater. In practice, it is crucial to create a compact, low cost and power saving instrument for the long-term deep-sea observation. A recently appeared diode-pumped solid-state (DPSS) laser seems to be a promising candidate as it is both compact and robust. Additionally, its high repetition rate up to hundreds of kHz can provide a considerable throughput for LIBS analysis. However, the DPSS lasers operate at moderate pulse energies, usually less than one mJ, which cannot sustain stable breakdowns in bulk water. To ensure stable laser-induced plasmas underwater with such a μJ-DPSS laser, we introduced an ultrasound source to assist the breakdown process. The phase interface and mass flow generated by the near-field ultrasound can greatly reduce the breakdown threshold and enhance element-specific emissions. Meanwhile, the high repetition-rate pulses can also improve the breakdown probability and generate unique emission lines originated from the water molecule. We further demonstrate that the high repetition-rate DPSS laser combined with the Echelle spectrometer can provide effective quantitative analysis for metal elements in bulk water. T2 - 10th Euro-Mediterranean Symposium on Laser-Induced Breakdown Spectroscopy, EMSLIBS 2019 CY - Czech, Brno DA - 08.09.2019 KW - Ultrasound KW - Underwater LIBS KW - µJ-DPSS laser KW - High repetition-rate PY - 2019 AN - OPUS4-49223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Burnage, Samual Charles A1 - Bell, Jérémy A1 - Gawlitza, Kornelia A1 - Wan, Wei A1 - Rurack, Knut T1 - Microfluidic Platform for Functionalisation, Extraction and Detection of Phosphorylated Amino Acids Using Fluorescent Sensory Particles N2 - The reliable identification and quantification of phosphorylated amino acids, peptides and proteins is one of the key challenges in contemporary bioanalytical research, noteworthy, to diagnose and treat diseases at an early developmental stage. Miniaturised sensing devices like microfluidic chips combined with “smart” detection chemistry, simple data assessment, processing and presentation are very attractive for benchtop use in clinical environments. We developed novel synthetic probes targeting phosphorylated amino acids, based on core-shell microparticles consisting of a silica core coated with a molecularly imprinted polymer (MIP) shell. These “plastic antibodies” are extremely robust, resist denaturing solvents and elevated temperatures, can be reproducibly produced at low cost, and potentially overcome many of the practical problems in current bioanalytical detection strategies. The MIP layer contains a fluorescent probe monomer, binds selectively to phosphorylated tyrosine (pTyr) with a significant imprinting factor higher than 3.5 and responds with a “lighting-up” of its fluorescence accompanied by the development of a strongly red-shifted emission band toward the analyte. In analogy to our previous work [4], the bead-based ratiometric detection scheme has also been successfully transferred to a microfluidic chip format to demonstrate its applicability to rapid assays. Such a miniaturised device could yield an automated pTyr measurement system in the future. The setup was built by coupling a modular microfluidic system [5] for amino acid functionalisation (Fmoc protection) and a multi-layer PDMS/Teflon/glass microfluidic chip [6] for buffering, extraction (micropillars co-flow extraction) and selective adsorption on the MIP core-shell particles. A miniaturised optical assembly for low-light fluorescence measurements was also developed. Based on small opto-electronic parts and optical fibres, the emission from the MIP particles upon addition of pTyr concentrations from 0.5 – 200 μM could be monitored in real-time. T2 - IMA 2019 CY - Ioaninna, Greece DA - 22.09.2019 KW - MIPs KW - Microfluidics KW - Fluorescence KW - Sensing PY - 2019 AN - OPUS4-49201 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Burnage, Samual Charles A1 - Bell, Jérémy A1 - Gawlitza, Kornelia A1 - Wan, Wei A1 - Rurack, Knut T1 - Microfluidic Platform for Functionalisation, Extraction and Detection of Phosphorylated Amino Acids Using Fluorescent Sensory Particles N2 - The reliable identification and quantification of phosphorylated amino acids, peptides and proteins is one of the key challenges in contemporary bioanalytical research, noteworthy, to diagnose and treat diseases at an early developmental stage1. Miniaturised sensing devices like microfluidic chips combined with “smart” detection chemistry, simple data assessment, processing and presentation are very attractive for benchtop use in clinical environments. We developed novel synthetic probes targeting phosphorylated amino acids, based on core-shell microparticles consisting of a silica core coated with a molecularly imprinted polymer (MIP) shell. These “plastic antibodies” are extremely robust, resist denaturing solvents and elevated temperatures, can be reproducibly produced at low cost, and potentially overcome many of the practical problems in current bioanalytical detection strategies. The MIP layer contains a fluorescent probe monomer, binds selectively to phosphorylated tyrosine (pY) with a significant imprinting factor higher than 3.5 and responds with a “lighting-up” of its fluorescence accompanied by the development of a strongly red-shifted emission band toward the analyte. In analogy to our previous work4, the bead-based ratiometric detection scheme has also been successfully transferred to a microfluidic chip format to demonstrate its applicability to rapid assays. Such a miniaturised device could yield an automated pY measurement system in the future. The setup was built by coupling a modular microfluidic system5 for amino acid functionalisation (Fmoc protection) and, as shown in Figure 1, a multi-layer PDMS/Teflon/glass microfluidic chip6 for buffering, extraction (micropillars co-flow extraction) and selective adsorption on the MIP core-shell particles. A miniaturised optical assembly for low-light fluorescence measurements was also developed. Based on small opto-electronic parts and optical fibres, the emission from the MIP particles upon addition of pY concentrations from 0.5-200 μM could be monitored in real-time. T2 - GSS2019 CY - BAM Adlershof, Berlin, Germany DA - 29.08.2019 KW - MIPs KW - Microfluidics KW - Sensing KW - Fluorescence PY - 2019 AN - OPUS4-49202 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jiang, Shan A1 - Wang, T. A1 - Gawlitza, Kornelia A1 - Persson, J. A1 - Rurack, Knut T1 - Carbon Nanodots (CNDs) Doped Molecularly Imprinted Polymers (MIPs) for Tumor- Associated Glycan Imaging N2 - Glycosylation is heavily altered in tumor cells compared with healthy cells, because of the different levels of expression of glycosyltransferases, glycosidases and monosaccharide transporters within a cancerous microenvironment. 1 Tumor-associated glycans, especially sialic acid (SA) conjugates, which are good candidates of tumor markers, can be used for Cancer early diagnosis. 2 However, studies on SA-binding lectins demonstrate that the type of SAlinkage and the glycosylation position of carbohydrate can greatly influence the affinity. 3 Therefore, there is a need for diagnostic tools owning high specificity and strong affinity to analyze and determine SA glycosylation motifs. 4 Herein, we report the development of fluorescent core/shell/shell nanoparticles where the outermost layer is a thin molecularly imprinted polymer (MIP) film binding to tumor cells in vitro by targeting cell surface SA. The core is made of N-doped red carbon nanodots (R-CNDs) which were prepared by hydrothermal synthesis, emitting intense red fluorescence under fluorescence microscopy imaging conditions. Silica coating of R-CNDs was achieved by a microemulsion method, resulting in ca. 40 nm large silica-coated CNDs (named R-CSNs). Finally, a thin MIP-shell was accomplished by using a combination of non-fluorescent monomer (3), functional monomers (1, 2) and cross-linker (EGDMA) for polymerization (Figure 1). Transmission electron microscopy (TEM) is used for structural characterization of the formation of MIP layer, and the results of cell-based binding tests show a promising binding affinity of MIPs to tumor cells, allowing a relatively robust, specific and rapid analytical method for cancer biopsies. T2 - GSSMIP2019 CY - Berlin, Germany DA - 28.08.2019 KW - MIP KW - Carbon Nanodots KW - Glycan PY - 2019 UR - https://sites.google.com/view/gssmip2019/gss-mip-2019 AN - OPUS4-49252 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zettner, Alina A1 - Gojani, Ardian A1 - Schmid, Thomas A1 - Gornushkin, Igor B. T1 - Evaluation of a Spatial Heterodyne Spectrometer for Raman Spectroscopy of Minerals N2 - Spatial heterodyne spectroscopy (SHS) is a novel spectral analysis technique that is being applied for Raman spectroscopy of minerals. This paper presents the theoretical basis of SHS and its application for Raman measurements of calcite, quartz and forsterite in marble, copper ore and nickel ore, respectively. The SHS measurements are done using a broadband (518–686 nm) and resolving power R ≈ 3000 instrument. The spectra obtained using SHS are compared to those obtained by benchtop and modular dispersive spectrometers. It is found that SHRS performance in terms of resolution is comparable to that of the benchtop spectrometer and better than the modular dispersive spectrometer, while the sensitivity of SHRS is worse than that of a benchtop spectrometer, but better than that of a modular dispersive spectrometer. When considered that SHS components are small and can be packaged into a handheld device, there is interest in developing an SHS-based Instrument for mobile Raman spectroscopy. This paper evaluates the possibility of such an application. KW - Forsterite KW - Spatial heterodyne spectrometer KW - Interferometric spectroscopy KW - Fourier transform spectroscopy KW - Raman spectroscopy KW - Calcite KW - Quartz PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504624 DO - https://doi.org/10.3390/min10020202 VL - 10 IS - 2 SP - 202 PB - MDPI CY - Basel, Switzerland AN - OPUS4-50462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Gaft, M. A1 - Nagli, L. A1 - Raichlin, Y. T1 - Laser-induced breakdown spectroscopy (LIBS) of BaF2-Tm3+ N2 - Our recent study was focused on the emission from Laser Induced Plasma (LIP) at the delay times of tenths of microseconds after the laser pulse. At these long delays, the spectrum is dominated by the broadband molecular emission and plasma induced luminescence (PIL) produced by a luminescent matrix; only solitary atomic emission lines can be seen. Barium fluoride BaF2 activated by thulium (Tm) is a famous scintillator that presents the promising object for LIP in terms of both the potential for BaF molecular emission and Tm3+ PIL. The detection of molecular and PIL bands presents a new opportunity for analysis of halogens and rare-earth elements, which are the difficult objects for LIBS. In this paper, we show that the UV, Green, Extreme Red, and Infrared molecular bands from BaF and blue luminescence from Tm3+ are present in the LIP emission spectra while the detection of atomic Emission from F I and Tm I was impossible with the same experimental setup. Thus, the detection of molecular emission and PIL can be more sensitive than the traditional detection of Emission from atoms and ions. KW - BaF KW - Laser-Induced Breakdown Spectroscopy (LIBS) KW - Rare-Earth elements (Tm3+) KW - Plasma-induced luminescence PY - 2020 DO - https://doi.org/10.1016/j.sab.2020.105767 VL - 164 SP - 105767 PB - Elsevier B.V. AN - OPUS4-50360 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gojani, Ardian A1 - Gornushkin, Igor B. T1 - Combined Raman and LIBS using Spatial Heterodyne Spectrometer with High Repetition Rate Laser N2 - Spatial heterodyne spectroscopy is used for Raman and laser-induced breakdown spectroscopy of six rocks with various mineral content, using high repetition rate diode-pumped solid state lasers. While LIBS data are obtained for all samples, Raman signal was determined only for half of those. This work shows that it is possible to combine LIBS and Raman spectrometry into a single instrument consisting of a DPSS laser for excitation and SHS for spectral recording. For better results and gain from complementary spectrochemical information that the system provides, it is necessary to optimize light collection. T2 - 2020 Winter Conference on Plasma Spectrochemistry CY - Tucson, Arizona, USA DA - 13.01.2020 KW - Laser-Induced Background Spectroscopy KW - Spatial heterodyne spectroscopy KW - Raman spectroscopy PY - 2020 AN - OPUS4-50265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Galbacs, G. A1 - Keri, A. A1 - Kalomista, I. A1 - Kovacs-Szeles, E. A1 - Gornushkin, Igor B. T1 - Deuterium analysis by inductively coupled plasma mass spectrometry using polyatomic species: An experimental study supported by plasma chemistry modeling N2 - based on the use of the signal from hydrogen-containing polyatomic ions formed in the inductively coupled plasma. Prior to analytical experiments, a theoretical study was performed to assess the concentration of polyatomic species present in an equilibrium Ar-O-D-H plasma, as a function of temperature and stoichiometric composition. It was established that the highest sensitivity and linearity measurement of D concentration in a wide range can be achieved by monitoring the ions of D2 and ArD, at masses 4 and 42, respectively. Results of the calculations are in good agreement with the experiments. Signal stability, spectral interferences, as well as the effect of plasma parameters were also assessed. Under optimized conditions, the limit of detection (LOD) was found to be 3 ppm atom fraction for deuterium when measured as ArD (in calcium and potassium free water), or 78 ppm when measured as D2. The achieved LOD values and the 4 to 5 orders of magnitude dynamic range easily allow the measurement of deuterium concentrations at around or above the natural level, up to nearly 100% (or 1 Mio ppm) in a standard quadrupole ICP-MS instrument. An even better performance is expected from the method in high resolution ICP-MS instruments equipped with low dead volume sample introduction systems KW - ICP MS KW - Deuterium KW - Deuterium enriched water PY - 2020 DO - https://doi.org/10.1016/j.aca.2020.01.011 VL - 1104 SP - 28 EP - 37 PB - Elsevier B.V. AN - OPUS4-50777 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Dell’Aglio, M. A1 - Motto-Ros, V. A1 - Pelascini, F. A1 - De Giacomo, A. T1 - Investigation on the material in the plasma phase by high temporally and spectrally resolved emission imaging during Pulsed Laser Ablation (PLAL) in Liquid for NPs production and consequent considerations on NPs formation N2 - In this paper experimental temperature and density maps of the laser induced plasma in water during Pulsed Laser ablation in Liquid (PLAL) for the production of metallic nanoparticles (NPs) has been determined. A detection system based on the simultaneous acquisition of two emission images at 515 and 410 nm has been constructed and the obtained images have been processed simultaneously by imaging software. The results of the data analysis show a variation of the temperature between 4000 and 7000 K over the plasma volume. Moreover, by the study of the temperature distribution and of the number densities along the plasma expansion axis it is possible to observe the condensation zone of the plasma where NPs can be formed. Finally, the time associated to the electron processes is estimated and the plasma charging effect on NPs is demonstrated. The set of observations retrieved from these experiments suggests the importance of the plasma phase for the growth of NPs and the necessity of considering the spatial distribution of plasma parameters for the understanding of one of the most important issues of the PLAL process, that is the source of solid material in the plasma phase. KW - LIBS KW - Laser induced plasma KW - Plasma modeling KW - Plasma diagnostics KW - Nanoparticle formation PY - 2019 DO - https://doi.org/10.1088/1361-6595/ab369b VL - 28 IS - 8 SP - Article Number: 085017 PB - IOP Publishing AN - OPUS4-48753 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huan, Y. A1 - Gojani, Ardian A1 - Gornushkin, Igor B. A1 - Wang, X. A1 - Liu, D. A1 - Rong, M. T1 - Dynamics of laser-induced plasma splitting N2 - The dynamics of laser-induced plasma plume splitting is investigated using spatiotemporal plasma imaging and spectrometry in this paper. Plasma plume splitting into fast and slow components is clearly observed using plasma optical emission as time evolves. The spatial resolved plasma spectra are used to investigate the plasma species distribution, which reveals that the charged copper ions, which radiate at wavelength range 485 nm - 504 nm, are merely present in the fast component. In order to further interpret the mechanism, the pressure-dependent and laser energy-dependent plume splitting are analyzed. Based on the results, the charge separation field is proposed to explain this phenomenon. This work can be of importance for such areas as laser induced breakdown spectroscopy, laser-induced ion source formation, pulse laser deposition, film growth, and nanoscale synthesis. KW - Spectroscopy KW - Laser induced plasma KW - Splitting KW - Imaging PY - 2020 DO - https://doi.org/10.1016/j.optlaseng.2019.105832 SN - 0143-8166 VL - 124 SP - 1 EP - 5 PB - Elsevier CY - Amsterdam AN - OPUS4-48746 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pauw, Brian Richard T1 - The Dark Side of Science N2 - The Joint Summer School of the two Marie Skłodowska-Curie Innovative Training Networks (ITN) “BioCapture” and “GlycoImaging”, funded by the EU within the Horizon 2020 framework programme, which are both devoted to the development of new methods for cancer biomarker and cancer cell detection, will take place at the Adlershof Campus of BAM. 19 Early stage researchers of both projects will convene, discuss their own science and plan future collaborative research. Training in scientific writing (instructor: Luita Spangler, Free University of Berlin), an employability workshop (Antti Kapanen, University of Applied Sciences Berlin) and first contacts with the “dark side of science” (Brian R. Pauw, BAM) will complement the programme of the summer school. T2 - EU-ITN-Summer School CY - Adlershof, Berlin, Germany DA - 26.08.2019 KW - Scientific communication KW - Scientific rigour KW - Scientific method PY - 2019 AN - OPUS4-48760 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kimani, Martha Wamaitha A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Dual-fluorescent sialic acid-imprinted polymer nanoparticles for staining of glycans on cancerous cells N2 - Cancer is a leading cause of death worldwide, and its early detection and resultant treatment contributes significantly to patient recovery and survival. Detection is currently based on magnetic resonance imaging and computed tomography, methods that are expensive, while processing of the results is time-consuming1. There is a need for low-cost cancer detection techniques that give conclusive results in the shortest time possible. When equipped with a reporter function, molecularly imprinted polymers (MIPs) targeting tumor markers on cancerous cells may provide a cheaper solution for imaging-based cancer detection. Thin MIP layers immobilized on particle platforms are ideal in this regard, because a fluorescence reporter can be integrated into the particle core and/or MIP shell and such core/shell nanoparticles show faster response times and increased selectivity in comparison to bulk MIPs. Changes in sialylation patterns of cell surface glycans indicate malignancy2. Here, we present the development of MIPs that target sialic acid-terminated glycans (SA MIPs), prepared as a thin layer on a polystyrene core/silica shell nanoparticle platform. The MIP particles contain fluorescent emitters and can be applied in fluorescence imaging of malignant tumors. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) are used for structural characterization. Binding capacity of the MIPs to target glycans and competing sugars is also evaluated and compared to that of the corresponding non-imprinted polymer particles (NIP). T2 - Graduate Student Symposium on Molecularly Imprinted Polymers CY - Berlin, Germany DA - 29.08.2019 KW - Cancer KW - Sialic acid KW - MIPs PY - 2019 AN - OPUS4-48826 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. A1 - Kazakov, Alexander Ya. T1 - Model of stimulated emission in aluminum laser-induced plasma produced by resonance pumping N2 - Stimulated emission observed experimentally in aluminum laser induced plasma is modeled via a kinetic approach. The simulated emission at several cascade transitions is created by a pump laser guided through the plasma at several microseconds after its creation and tuned in resonance with the strong transition at 266 nm. A two-dimensional space-time collisional radiative plasma model explains the creation of the population inversion and lasing at wavelengths 2.1 μm and 396.1 nm. The population inversion for lasing at 2.1 μm is created by depopulation of the ground state and population of the upper state via absorption of resonant radiation at 266 nm. The population inversion for lasing at 396.1 nm occurs during the laser pulse via the decay of the population of the pumped upper state to the lasing state via cascade transitions driven optically and by collisions. The model predicts that the population inversion and corresponding gain may reach high values even at moderate pump energies of several μJ per pulse. The efficiency of lasing at 2.1 μm and 396.1 nm is estimated to be on the order of a percent of laser pump energy. The polarization effect that the pump radiation at 266 nm imposes on the stimulated emission at 396.1 nm is discussed. The calculated results are favorably compared to experiment. T2 - FLAMN, June 30- July 4 2019 CY - St. Petersburg, Russia DA - 30.06.2019 KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Plasma diagnostics PY - 2019 AN - OPUS4-48598 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gojani, Ardian A1 - Palásti, David J. A1 - Paul, Andrea A1 - Galbács, G. A1 - Gornushkin, Igor B. T1 - Analysis and classification of liquid samples by spatial heterodyne spectroscopy N2 - Spatial heterodyne spectroscopy (SHS) is used for quantitative analysis and classification of liquid samples. SHS is a version of a Michelson interferometer with no moving parts and with diffraction gratings in place of mirrors. The instrument converts frequency-resolved information into spatially resolved one and records it in the form of interferograms. The back-extraction of spectral information is done by the Fast Fourier transform. A SHS instrument is constructed with the resolving power 5000 and spectral range 522 - 593 nm. Two original technical solutions are used as compared to previous SHS instruments: the use of a high frequency diode pumped solid state (DPSS) laser for excitation of Raman spectra and a microscope-based collection system. Raman spectra are excited at 532 nm at the repetition rate 80 kHz. Raman shifts between 330 cm-1 and 1600 cm-1 are measured. A new application of SHS is demonstrated: for the first time it is used for quantitative Raman analysis to determine concentrations of cyclohexane in isopropanol and glycerol in water. Two calibration strategies are employed: univariate based on the construction of a calibration plot and multivariate based on partial least square regression (PLSR). The detection limits for both cyclohexane in isopropanol and glycerol in water are at a 0.5 mass% level. In addition to the Raman-SHS chemical analysis, classification of industrial oils (biodiesel, poly(1-decene), gasoline, heavy oil IFO380, polybutenes, and lubricant) is performed using their Raman-fluorescence spectra and principal component analysis (PCA). The oils are easily discriminated as they show distinct non-overlapping patterns in the space of principal components. KW - Spectroscopy KW - Atomic KW - Laser induced breakdown KW - Lasers PY - 2019 DO - https://doi.org/10.1177/0003702819863847 SN - 1943-3530 VL - 73 IS - 12 SP - 1409 EP - 1419 PB - Sage AN - OPUS4-48599 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Calibration-free LIBS of steel samples N2 - An improved algorithm for calibration-free laser induced breakdown spectroscopy (CF LIBS) is presented which includes several novel features in comparison with previously proposed similar algorithms. In particular, it allows using spectral lines with arbitrary optical thickness for the construction of Saha-Boltzmann plots, retrieves the absorption path length (plasma diameter) directly from a spectrum, replaces the Lorentzian line profile function by the Voigt function, and allows for self-absorption correction using pre-calculated and tabulated data rather than approximating functions. The tabulated data embody the solutions of the radiative transfer equation for numerous combinations of optical thicknesses and line widths. The algorithm is used to analyze 100 low alloy steel spectra. T2 - 20.06.2019 LTB workshop on LIBS analysis of steel CY - Berlin, LTB, Germany DA - 20.06.2019 KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Plasma diagnostics KW - Chemical reactors PY - 2019 AN - OPUS4-48600 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. A1 - Palásti, David J. A1 - Veres, M. A1 - Rigó, I. A1 - Geretovszky, Z. A1 - Kovács-Széles, É. A1 - Gojani, Ardian A1 - Galbács, Gábor T1 - Optimization and detailed spectroscopic characterization of an improved SH-LIBS setup N2 - The spatial heterodyne detection principle has a great potential in spectroscopy. It has an optical setup similar to that of a Michelson interferometer, with the mirrors replaced by diffraction gratings positioned at fixed, equal distances from the beamsplitter and are slightly tilted. The resulting interference pattern is recorded by a digital camera and the spectrum is recovered by using Fourier transformation. Although SHS was initially developed for astronomical and satellite-based atmospheric measurements, but in recent years it has been started to be applied in other branches of spectroscopy too. Recently the area of laser-induced breakdown spectroscopy (LIBS) has also discovered the potential of SHS. The main appeal of SHS detection in LIBS includes the compactness and robustness of the setup (in view of field applications) and the flexibility to optimize the setup for either high sensitivity or for high resolution, which can be benficially exploited in applications like stand-off measurements, quantitative analysis with isotope resolution, etc. In the present work, we have improved and further optimized our initial LIBS-SHS setup described in a previous conference. By using optical simulations, we have modelled the light transmission efficiency, instrumental function and imaging properties of the system. We significantly improved and automated the spectral and image data processing sequence. The optimizations carried out resulted in an improved spectral resolution and repeatability, a lower spectral background and the elimination of the central line artifact originating from the Fourier transformation procedure. A detailed characterization of the LIBS spectroscopy performance (e.g. resolution, spectral coverage, tuning range, linearity, etc.), including a comparison with that of a LIBS setup based on a conventional dispersion CCD spectrometer was also performed. T2 - European Winter Conference on Plasma Spectrochemistry (EWSPS-2019) CY - Pau, France DA - 03.02.2019 KW - SHS KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Spatial heterodyne spectrometer PY - 2019 AN - OPUS4-48047 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tillo, Adam A1 - Bartelmeß, Jürgen A1 - Chauhan, Vraj P. A1 - Bell, Jérémy A1 - Rurack, Knut T1 - Microfluidic Device for the Determination of Water Chlorination Levels Combining a Fluorescent meso-Enamine Boron Dipyrromethene Probe and a Microhydrocyclone for Gas Bubble Separation N2 - Chlorination procedures are commonly applied in swimming pool water and wastewater treatment, yet also in food, pharmaceutical, and paper production. The amount of chlorine in water needs to be strictly controlled to ensure efficient killing of pathogens but avoid the induction of negative health effects. Miniaturized microfluidic fluorescence sensors are an appealing approach here when aiming at online or at-site measurements. Two meso-enamine-substituted boron dipyrromethene (BODIPY) dyes were found to exhibit favorable indication properties, their reaction with hypochlorite leading to strong fluorescence enhancement. Real-time assays became possible after integration of these fluorescent probes with designed two-dimensional (2D) and three-dimensional (3D) microfluidic chips, incorporating a passive sinusoidal mixer and a microhydrocyclone, respectively. A comparison of the two microfluidic systems, including their abilities to prevent accumulation or circulation of microbubbles produced by the chemical indication reaction, showed excellent fluidic behavior for the microhydrocyclone-based device. After coupling to a miniaturized optical reader for fluorescence detection, the 2D microfluidic system showed a promising detection range of 0.04−0.5 mg L−1 while still being prone to bubble-induced fluctuations and suffering from considerably low signal gain. The microhydrocyclone-based system was distinctly more robust against gas bubbles, showed a higher signal gain, and allowed us to halve the limit of detection to 0.02 mg L−1. The use of the 3D system to quantify the chlorine content of swimming pool water samples for sensitive and quantitative chlorine monitoring was demonstrated. KW - Chlorine KW - BODIPY KW - Fluorescence KW - Micro-Hydrocyclone KW - Microfluidic Chip PY - 2019 DO - https://doi.org/10.1021/acs.analchem.9b03039 SN - 0003-2700 VL - 91 IS - 20 SP - 12980 EP - 12987 PB - American Chemical Society CY - Washington, DC AN - OPUS4-49393 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pignatelli, Giuseppe A1 - Strasse, Anne A1 - Gornushkin, Igor B. A1 - Gumenyuk, Andrey T1 - Optical Sensor for Monitoring Quality of 3D Metal Printing N2 - Additive Manufacturing (AM) becomes widespread in many technological fields including the precise machining of steel. To assure quality of final products, thorough monitoring of online process is required. We test several monitoring techniques during the AM printing to quickly detect and possibly correct flaws while building a workpiece. Here we show how optical emission spectroscopy can be used to recognize defects that are artificially introduced on a steel printing substrate. T2 - Scix 2020 CY - Online meeting DA - 12.10.2020 KW - Additive manufacturing KW - Spectroscopy KW - Analytical chemistry PY - 2020 AN - OPUS4-51858 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sennikov, P. A1 - Gornushkin, Igor B. A1 - Kornev, R. A1 - Nazarov, V. A1 - Polyakov, V. A1 - Shkrunin, V. T1 - Hydrogen Reduction of MoF6 and Molybdenum Carbide Formation in RF Inductively Coupled Low‑Pressure Discharge: Experiment and Equilibrium Thermodynamics Consideration N2 - The physical plasma parameters, temperature and electron number density, are studied in the RF-IC (RF inductively coupled) discharge at a reduced pressure of 3 Torr in mixtures of MoF6 with Ar, H2 and CH4. The emission spectra of mixtures are investigated. It is shown that in the presence of argon, the concentration of free electrons in plasma and dissociation rate of MoF6 increase. A main role of molecular hydrogen is the generation of atomic hydrogen that binds atomic fuorine and leads to the formation of gaseous and solid products. Exhaust gas mixtures exiting the reactor are analyzed by mass spectrometry. It is shown that for all cases, the conversion of MoF6 into reaction products is close to 100%. A thermodynamic analysis of the equilibrium composition of MoF6 systems with Ar, H2 and CH4 was carried out and the obtained results are in good agreement with experimentally observed composition of the solid and gas phases. Analysis of solid deposits from mixture MoF6/H2/Ar revealed the presence of molybdenum powder and large amount of amorphous MoFx. The deposit obtained from mixtures with methane, MoF6/H2/Ar/CH4, contained crystalline molybdenum carbide, Mo3C2. KW - Molybdenum carbide KW - RF ICP discharge KW - Reduction of MoF6 KW - Thermodynamic KW - Molybdenum PY - 2020 DO - https://doi.org/10.1007/s11090-020-10138-3 SN - 0272-4324 VL - 41 IS - 2 SP - 673 EP - 690 PB - Springer AN - OPUS4-51569 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. A1 - Sennikov, P. T1 - Laser induced gas breakdown in reactive mixtures containing halides of boron and silicon: diagnostics and modeling N2 - We run two pilot LIP experiments in reactive gas mixtures. First, LIP is excited in BCl3 or BF3 plus H2 or CH4 to evaluate the efficiency of deposition of solid boron and boron carbide, materials that are largely used for refractory coatings. Second, we investigate a possibility of synthesis of fluorochlorosilanes SiFxCl4-x (x = 1, 2, 3) by LIP induced in SiF4+SiCl4 gas mixtures. Using fluorochlorosilanes with different combinations of F and Cl in the SiFxCly molecule may add flexibility in processes of silicon deposition and etching. The gases used and solid deposits are analyzed by optical emission spectroscopy (OES) and IR and mass spectrometry (MS). We also model the laser induced plasma by performing static equilibrium chemistry calculations to see whether desired reaction products are thermodynamically favorable and dynamic calculations of the expanding plasma plume to see how and where the products form. T2 - International Workshop on Laser Induced breakdown Spectroscopy CY - Online meeting DA - 01.12.2020 KW - Silicon halides KW - Chemical vapor deposition KW - Laser induced dielectric breakdown KW - Hydrogen reduction PY - 2020 AN - OPUS4-51725 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kepes, E. A1 - Gornushkin, Igor B. A1 - Pořízka, P. A1 - Kaiser, J T1 - Spatiotemporal spectroscopic characterization of plasmas induced by non-orthogonal laser ablation N2 - Ablation geometry significantly affects the plasma parameters and the consequent spectroscopic observations in laser-induced breakdown spectroscopy. Nevertheless, plasmas induced by laser ablation under inclined incidence angles are studied to a significantly lesser extent compared to plasmas induced by standard orthogonal ablation. However, inclined ablation is prominent in stand-off applications, such as the Curiosity Mars rover, where the orthogonality of the ablation laser pulse cannot be always secured. Thus, in this work, we characterize non-orthogonal ablation plasmas by applying plasma imaging, tomography, and spectral measurements. We confirm earlier observations according to which non-orthogonal ablation leads to a laser-induced plasma that consists of two distinct parts: one expanding primarily along the incident laser pulse and one expanding along the normal of the sample surface. Moreover, we confirm that the former emits mainly continuum radiation, while the latter emits mainly sample-specific characteristic radiation. We further investigate and compare the homogeneity of the plasmas and report that inclined ablation affects principally the ionic emissivity of laser-induced plasmas. Overall, our results imply that the decreased fluence resulting from inclined angle ablation and the resulting inhomogeneities of the plasmas must be considered for quantitative LIBS employing non-orthogonal ablation. KW - Radon transformation KW - Laser induced plasma KW - Plasma tomography PY - 2020 DO - https://doi.org/10.1039/d0an01996h VL - 146 IS - 3 SP - 920 EP - 929 PB - The Royal Society of Chemistry AN - OPUS4-51774 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -