TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Rades, Steffi A1 - Salge, T. A1 - Mielke, Johannes A1 - Ortel, Erik A1 - Schmidt, R. T1 - Characterisation of nanoparticles by means of high-resolution SEM/EDS in transmission mode N2 - Advances in scanning electron microscopy (SEM) enable the high-resolution imaging of single nanoparticles (NPs) with sizes well below 10 nm. The SEM analysis in transmission mode (T-SEM) of NPs on thin film supports has many benefits when compared to the analysis of NPs on bulk substrates. The enhanced material (mass – thickness) contrast of the T-SEM imaging mode is well suited for in-depth and, particularly valuable, to very accurate, traceable, lateral dimensional measurements of NPs. Compared to samples prepared on bulk substrates, T-SEM with energy dispersive X-ray spectroscopy (EDS) achieves a drastically improved spatial resolution of the emitted X-rays. The poor signal-to-noise ratio of the X-ray spectra emitted by a single nanoparticle (NP) can be improved by the use of high-sensitivity (high collection solid angle) silicon drift (SDD), energy-dispersive X-ray spectrometers (EDS). The EDS spectral imaging of a single NP with a spatial resolution below 10 nm has become possible. This is demonstrated by means of various examples of nanostructures. Advanced data processing of T-SEM/EDS results sets the stage for the automated classification of NPs by feature analysis. This method combines the detection of morphological structures of interest by image processing of T-SEM micrographs with the chemical classification by EDS. T2 - European Microbeam Analysis Society’s 14th European Workshop on Modern Developments and Applications in Microbeam Analysis (EMAS 2015) CY - Portorož, Slovenia DA - 03.05.2015 KW - High-resolution KW - SEM KW - T-SEM KW - EDX KW - Nanoparticles PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-355628 UR - http://iopscience.iop.org/article/10.1088/1757-899X/109/1/012006 DO - https://doi.org/10.1088/1757-899X/109/1/012006 SN - 1757-899X VL - 109 SP - 012006-1 EP - 012006-12 PB - IOP Publishing Ltd CY - Bristol, UK AN - OPUS4-35562 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Yamamoto, K. A1 - Grulke, E. A. T1 - Size and shape distribution of bipyramidal TiO2 nanoparticles by transmission electron microscopy – an inter-laboratory comparison N2 - Extraction of true, 3D shape (and size) of non-spherical nanoparticles (NPs) is associated with errors by conventional 2D electron microscopy using projection images. Significant efforts within the ISO technical committee TC 229 ‘Nanotechnologies’ are aimed at establishing accurate TEM and SEM measurement of NP size and shape as robust, standard procedures. Study groups have been organizing inter-laboratory comparisons on well-selected NP systems according to the market needs, such as aggregated titania nano-powder for which size and shape distribution of primary crystallites of irregular shape must be measured accurately. To be noticed is e. g. the fact that the measurement procedure allows only manual selection of the particles clearly distinguishable for analysis as well as manual definition of the contour of the imaged NPs. An inter-laboratory exercise on titania NPs (pure anatase, grown by hydrothermal synthesis) of well-defined non-spherical shape, i.e. bipyramidal has been recently started within ISO/TC 229 under similar conditions as for the irregular shaped titania. Overlapped particles were allowed to be considered, as long as they are clearly distinguishable. One decisive NP selection criterion was to analyze only those NPs with a roundness value below 0.7, i.e. the NPs laying on the support foil and, hence, with projection areas clearly deviating from perfect circles (R=1). The overall evaluation (for 15 labs) of the size descriptors (area, Feret, minFeret, perimeter) and shape descriptors (aspect ratio, roundness, compactness, extent) by analysis of variance is just to be finished and included in ISO/WD 21363 Nanotechnologies -- Protocol for particle size distribution by transmission electron microscopy. KW - Nanoparticles KW - Electron microscopy KW - Titanium oxide KW - Particle size distribution PY - 2018 UR - https://www.cambridge.org/core/journals/microscopy-and-microanalysis/article/size-and-shape-distribution-of-bipyramidal-tich-nanoparticles-by-transmission-electron-microscopy-an-interlaboratory-comparison/9E2FA0C716DB5F881E3032D014DFD52B DO - https://doi.org/10.1017/S1431927618009017 SN - 1431-9276 SN - 1435-8115 VL - 24 IS - S1 (August 2018) SP - 1706 EP - 1707 PB - Cambridge University Press CY - New York, NY, U.S.A. AN - OPUS4-46005 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hsiao, I.-L. A1 - Bierkandt, Frank A1 - Reichardt, Ph. A1 - Luch, A. A1 - Huang, Y.-J. A1 - Jakubowski, Norbert A1 - Tentschert, J. A1 - Haase, A. T1 - Quantification and visualization of cellular uptake of TiO2 and Ag nanoparticles: comparison of different ICP-MS techniques N2 - Safety assessment of nanoparticles (NPs) requires techniques that are suitable to quantify tissue and cellular uptake of NPs. The most commonly applied techniques for this purpose are based on inductively coupled plasma mass spectrometry (ICP-MS). Here we apply and compare three different ICP-MS methods to investigate the cellular uptake of TiO2 (diameter 7 or 20 nm, respectively) and Ag (diameter 50 or 75 nm, respectively) NPs into differentiated mouse neuroblastoma cells (Neuro-2a cells). Cells were incubated with different amounts of the NPs. Thereafter they were either directly analyzed by laser ablation ICP-MS (LA-ICP-MS) or were lysed and lysates were analyzed by ICP-MS and by single particle ICP-MS (SP-ICP-MS). KW - Nanoparticles KW - Single particle ICP-MS KW - Laser ablation ICP-MS KW - Cellular internalization KW - Neurons PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-371620 DO - https://doi.org/10.1186/s12951-016-0203-z SN - 1477-3155 VL - 14 SP - Article 50 AN - OPUS4-37162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hunter, R. D. A1 - Hayward, E. C. A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Kulak, A. A1 - Guan, S. A1 - Schnepp, Z. T1 - The effect of nitrogen on the synthesis of porous carbons by iron-catalyzed graphitization N2 - This paper reports a systematic study into the effect of nitrogen on iron-catalyzed graphitization of biomass. Chitin, chitosan, N-acetylglucosamine, gelatin and glycine were selected to represent nitrogen-rich saccharides and amino-acid/polypeptide biomass precursors. The materials were pyrolyzed with an iron catalyst to produce carbons with a wide range of chemical and structural features such as mesoporosity and nitrogen-doping. Many authors have reported the synthesis of nitrogen-doped carbons by pyrolysis and these have diverse applications. However, this is the first systematic study of how nitrogen affects pyrolysis of biomass and importantly the catalytic graphitization step. Our data demonstrates that nitrogen inhibits graphitization but that some nitrogen survives the catalytic graphitization process to become incorporated into various chemical environments in the carbon product. KW - Graphitization KW - Nanoparticles KW - Nanocomposite KW - Porous carbon KW - Nitrogen KW - Scattering PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575351 DO - https://doi.org/10.1039/d3ma00039g VL - 4 SP - 2070 EP - 2077 PB - Royal Society of Chemistry AN - OPUS4-57535 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hörenz, Christoph T1 - Preparation of Nanoparticulate Samples for Electron Microscopy N2 - This presentation addresses the importance of proper sample preparation to obtain suitable samples for electron microscopic measurements. The objective as well as the requirements are discussed. Further, different sample deposition methods for various types of nanoparticulate samples are shown. T2 - nPSize Web Conference CY - Online meeting DA - 23.07.2020 KW - Nanoparticles KW - Electron microscopy KW - Sample preparation KW - Particle size distribution KW - Particle number concentration PY - 2020 AN - OPUS4-51047 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hörenz, Christoph A1 - Pellegrino, F. A1 - Maurino, V. A1 - Taché, O. A1 - Bartczak, D. A1 - Cuello Nuñez, S. A1 - Abad Álvaro, I. A1 - Goenaga Infante, H. A1 - Hodoroaba, Vasile-Dan T1 - Improved Sample Preparation for the Analysis of Nanoparticles by Electron Microscopy N2 - In this work, we present various promising sample preparation procedures aiming to avoid drying artifacts and guarantee homogeneously distributed NP samples for imaging techniques like TEM, SEM or AFM. This involves retarded drying in an environment of high relative humidity as well as spin coating or freeze drying of the sample on the substrate. Depending on the type of the NPs, different techniques are successful in obtaining homogenous sample deposition. Simple drying at ambient conditions often results in heavily agglomerated NPs densely packed in coffee ring traces. Retardation of the drying speed in an environment of high relative humidity, however, yields homogeneous NP deposition in the case of bimodal SiO2 and bimodal gold NP’s. In contrast, a sample of bipyramidal TiO2, heavily agglomerated when commonly dried, is successfully dispersed by spin coating the suspension on the substrate. The analysis of the particle size distribution of the bimodal silica and gold samples yielded number ratios resembling the nominal number ratios. The reliable measurement of the NP concentration of polydisperse samples by electron microscopy, even if relative, is new and of special relevance because up to now only the size of the particles, i.e. the abscissa of the PSD, can be measured reliably. T2 - NANOSAFE 2020 CY - Online meeting DA - 16.11.2020 KW - Nanoparticles KW - Particle size distribution KW - Electron microscopy KW - Bimodal KW - SiO2 KW - Gold PY - 2020 AN - OPUS4-51714 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hörenz, Christoph T1 - Improved Sample Preparation for the Analysis of Nanoparticles by Electron Microscopy N2 - Various promising sample preparation procedures aiming to avoid drying artifacts and guarantee homogeneously distributed NP samples for imaging techniques like TEM, SEM or AFM are presented. This involves retarded drying in an environment of high relative humidity as well as spin coating or freeze drying of the sample on the substrate. Depending on the type of the NPs, different techniques are successful in obtaining homogenous sample deposition. Simple drying at ambient conditions often results in heavily agglomerated NPs densely packed in coffee ring traces. Retardation of the drying speed in an environment of high relative humidity, however, yields homogeneous NP deposition in the case of bimodal SiO2 and bimodal gold NP’s. In contrast, a sample of bipyramidal TiO2, heavily agglomerated when commonly dried, is successfully dispersed by spin coating the suspension on the substrate. The analysis of the particle size distribution of the bimodal silica and gold samples yielded number ratios resembling the nominal number ratios. The reliable measurement of the NP concentration of polydisperse samples by electron microscopy, even if relative, is new and of special relevance because up to now only the size of the particles, i.e. the abscissa of the PSD, can be measured reliably. T2 - EMPIR nPSize Training Course "Metrology for Measurement of Nanoparticle Size by Electron Microscopy and Atomic Force Microscopy" CY - Online meeting DA - 27.10.2020 KW - Nanoparticles KW - Particle size distribution KW - Sample peparation KW - Electron microscopy PY - 2020 AN - OPUS4-51716 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hörenz, Christoph A1 - Tache, O. A1 - Bartczak, D. A1 - Nunez, S. A1 - Abad Alvaro, I. A1 - Goenaga-Infante, H. A1 - Hodoroaba, Vasile-Dan T1 - A Study on the Analysis of Particle Size Distribution for Bimodal Model Nanoparticles by Electron Microscopy N2 - The present study addresses the capability of measurement of relative particle number concentration by scanning electron microscopy for model bimodal silica and gold samples prepared in the frame of the European research project “nPSize - Improved traceability chain of nanoparticle size measurements” as candidate reference nanoparticles. KW - Nanoparticles KW - Particle size distribution KW - Bimodal size distribution KW - Traceability PY - 2020 DO - https://doi.org/10.1017/S1431927620021054 VL - 26 IS - S2 SP - 2282 EP - 2283 PB - Cambridge University Press CY - Cambridge, UK AN - OPUS4-51771 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 - CONF A1 - Iannarelli, L. A1 - Giovanozzi, A. M. A1 - Diomede, L. A1 - Morelli, F. A1 - Viscotti, F. A1 - Maurino, V. A1 - Bigini, P. A1 - Martra, G. A1 - Spoto, G. A1 - Ortel, Erik A1 - Hodoroaba, Vasile-Dan A1 - Rossi, A. M. T1 - Shape engineered TiO2 nanoparticles in Caenorhabditis elegans: a Raman imaging based approach to assist tissue-specific toxicological studies N2 - In vivo detailed spatial distribution of TiO2 NPs was here investigated for the first time using a 2D chemical imaging analysis based on Confocal Raman Spectroscopy. The invertebrate nematode C. elegans was employed as prototypical model of living organism. Rod, bipyramidal and quasi-spherical engineered TiO2 NPs with different primary particle sizes and agglomeration states were prepared, characterized and then administered to nematodes. Exploiting the typical fingerprint of TiO2 in the Raman spectrum, we monitored the biodistribution of NPs inside the worm using a non-invasive, label-free method. The high spatial resolution chemical imaging and the specificity of the Raman technique in the localization of TiO2 NPs helped in the design of behavioral C. elegans studies aimed at elucidating the relationship among the size, shape, and agglomeration state of NPs and their ability to induce specific toxic effects. T2 - 16th European Conference on Applications of Surface and Interface Analysis ECASIA'15 CY - Fortaleza, Brazil DA - 14.08.2016 KW - TiO2 KW - Nanoparticles KW - Raman imaging KW - Toxicological studies PY - 2016 AN - OPUS4-38240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert A1 - Müller, L. A1 - Traub, Heike A1 - Esteban-Fernández, D. A1 - Panne, Ulrich A1 - Wanka, Antje A1 - Kneipp, J. T1 - Method development for metal detection at cellular levels by ICP-MS N2 - An overview about different analytical approaches will be presented of how to detect metals in individual biological cells by use of ICP-MS. For this purpose, we are using different sample introduction systems for ICP-MS for detection, imaging and quantification of metals at cellular levels. By use of laser ablation, we have studied the up-take by and distribution of nanoparticles in single cells. Recently we have developed staining techniques to measure protein and DNA content of cells and identifying the cell status by immunoassays using metal-tagging of antibodies. New research based on cell arrays will be shortly discussed. Using pneumatic nebulization and microdroplet generation, we have also studied the up-take of nanoparticles and toxic metals as well as essential elements in single cells using different ICP-MS mass spectrometric concepts (sector field instrument, triple-quad instrument, time of flight (CyTOF) instrument). The different ICP-MS based methods will be compared concerning their analytical figures of merit and their strengths and weaknesses will be evaluated. T2 - Projektmeeting CY - Bremen, Germany DA - 18.04.2018 KW - Single cell ICP-MS KW - LA-ICP-MS with cellular resolution KW - Nanoparticles PY - 2018 AN - OPUS4-44851 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert A1 - Müller, L. A1 - Traub, Heike A1 - Esteban-Fernández, D. A1 - Panne, Ulrich A1 - Wanka, Antje A1 - Schellenberger, E. A1 - Theuring, F. A1 - Kneipp, J. T1 - Method development for metal detection at cellular levels by ICP-MS N2 - An overview about different analytical approaches will be presented of how to detect metals in individual biological cells by use of ICP-MS. For this purpose, we are using different sample introduction systems for ICP-MS for detection, imaging and quantification of metals at cellular levels. By use of laser ablation, we have studied the up-take by and distribution of nanoparticles in single cells. Recently we have developed staining techniques to measure protein and DNA content of cells and identifying the cell status by immunoassays using metal-tagging of antibodies. New research based on cell arrays will be shortly discussed. Using pneumatic nebulization and microdroplet generation, we have also studied the up-take of nanoparticles and toxic metals as well as essential elements in single cells using different ICP-MS mass spectrometric concepts (sector field instrument, triple-quad instrument, time of flight (CyTOF) instrument). The different ICP-MS based methods will be compared concerning their analytical figures of merit and their strengths and weaknesses will be evaluated. T2 - ACS Annual Meeting CY - New Orleans, LA, USA DA - 18.03.2018 KW - Single cell ICP-MS KW - LA-ICP-MS with cellular resolution KW - Nanoparticles PY - 2018 AN - OPUS4-44799 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert A1 - Müller, L. A1 - Traub, Heike A1 - Esteban-Fernández, D. A1 - Panne, Ulrich A1 - Wanka, Antje A1 - Kneipp, J. T1 - Method development for metal detection at cellular levels by ICP-MS N2 - An overview about different analytical approaches will be presented of how to detect metals in individual biological cells by use of ICP-MS. For this purpose, we are using different sample introduction systems for ICP-MS for detection, imaging and quantification of metals at cellular levels. By use of laser ablation, we have studied the up-take by and distribution of nanoparticles in single cells. Recently we have developed staining techniques to measure protein and DNA content of cells and identifying the cell status by immunoassays using metal-tagging of antibodies. New research based on cell arrays will be shortly discussed. Using pneumatic nebulization and microdroplet generation, we have also studied the up-take of nanoparticles and toxic metals as well as essential elements in single cells using different ICP-MS mass spectrometric concepts (sector field instrument, triple-quad instrument, time of flight (CyTOF) instrument). The different ICP-MS based methods will be compared concerning their analytical figures of merit and their strengths and weaknesses will be evaluated. T2 - 16th Czech-Slovak Spectroscopic Conference CY - Luhacovice, Czech Republic DA - 27.05.2018 KW - Single cell analysis KW - ICP-MS KW - Nanoparticles PY - 2018 AN - OPUS4-45161 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert A1 - Müller, L. A1 - Traub, Heike A1 - Panne, Ulrich A1 - Herrmann, Antje A1 - Kneipp, J. T1 - The quantitative elemental microscope: for what is it good for? N2 - Elemental imaging of biological samples using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) provides spatially resolved information on element distribution in thin sections. By rastering with a laser across the sample, a two-dimensional image of the elemental distribution can be reconstructed that shows the intensities of the respective elements. Using overlapping laser shots the area ablated from single cells or thin sections (thickness 5 to 10 µm) can be reduced significantly so that the pixel size of the intensity measurement is significantly reduced. Having in mind that a laser shot ablates thin biological samples completely, we can make use of a new concept for calibration in the laser ablation method: the concept of total consumption. This calibration strategy allows production of simple matrix matched standards and provides an internal standardisation by ink jet technology, where a metal containing inks is printed on as thin layer on top of a biological sample. Different applications will be presented where our concepts have been applied. In the first example we used nanoparticle suspension of given particle numbers to quantify the uptake of metallic nanoparticles by biological cells. In the second example antibodies have been tagged by metals to measure protein expression in prostata cancer. In this approach application of house keeping proteins are investigated additionally to compensate variations in thickness and density of the biopsy samples. In the third application different nephrotoxic behaviour of Pt containing drugs have been investigated to study the local enrichement in kidney samples of mice treated with these three different compounds. Here the internal standard is required to allow intercomparisons between different individual mouse tissues. At the end of the lecture future trends will be discussed for elemental microscopy. T2 - European Winter Conference on Plasma Spectrochemistry 2017 CY - Sankt Anton am Arlberg, Austria DA - 19.02.2017 KW - LA-ICP-MS KW - Bioimaging KW - Nanoparticles KW - Biomarker PY - 2017 AN - OPUS4-39267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert A1 - Müller, L. A1 - Hösl, S. A1 - Traub, Heike A1 - Esteban-Fernández, D. A1 - Herrmann, Antje A1 - Panne, Ulrich T1 - Metal detection at cellular levels by use of laser ablation ICP-MS N2 - We are using laser ablation (LA)-ICP-MS to image the local distribution of elements (metals and hetero-elements) directly or (metallo-)proteins by metal-tagged antibodies in cells and tissue indirectly. Different applications will be discussed to demonstrate the state of the art and to visualize the elemental distribution pattern in soft bio-materials (tissue, single cells). In the first application Pt-containing drugs for cancer treatment are investigated and elemental distribution pattern are shown for tissue samples from animal experiments. Different standardization and quantification schemes including isotope dilution analysis will be discussed. In the second application, which is dedicated to toxicological research, the up-take of nano-particles by single cells are discussed and metal containing stains are used to visualize the distribution of nano-particles, proteins and DNA in a single cell simultaneously. This information is correlated with the distribution of the nanoparticles to identify the cell compartments where nano-particles are enriched. Quantification schemes have been developed to transform the measured intensities into number of particles up taken by the cells. In the third and last application LA-ICP-MS is applied to visualize the local distribution of proteins, which are used as bio-markers for prostate cancer. For this purpose, biopsy samples from patients have been simultaneously stained by eight differently metal-tagged antibodies in a multiplex approach. Detection of house-keeping proteins serves as internal standards to overcome differences in protein expression. Additionally ink-jet printing of metal doped inks onto the surface of these tissue samples has been applied for internal standardization and drift corrections. Finally future trends to develop an “elemental microscope” will be discussed. T2 - PITTCON 2017 CY - Chicago, IL, USA DA - 05.03.2017 KW - Element-microscopy KW - LA-ICP-MS KW - Nanoparticles KW - Immuno-assays PY - 2017 AN - OPUS4-39364 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert A1 - Müller, L. A1 - Traub, Heike A1 - Esteban-Fernández, D. A1 - Panne, Ulrich A1 - Wanka, Antje A1 - Schellenberger, E. A1 - Theuring, F. A1 - Kneipp, J. T1 - Method development for metal detection at cellular levels N2 - An overview about different analytical approaches will be presented of how to detect metals in individual biological cells by use of ICP-MS. For this purpose, we are using different sample introduction systems for ICP-MS for detection, imaging and quantification of metals at cellular levels. By use of laser ablation, we have studied the up-take by and distribution of nanoparticles in single cells. Recently we have developed staining techniques to measure protein and DNA content of cells and identifying the cell status by immunoassays using metal-tagging of antibodies. New research based on cell arrays will be shortly discussed. Using pneumatic nebulization and microdroplet generation, we have also studied the up-take of nanoparticles and toxic metals as well as essential elements in single cells using different ICP-MS mass spectrometric concepts (sector field instrument, triple-quad instrument, time of flight (CyTOF) instrument). The different ICP-MS based methods will be compared concerning their analytical figures of merit and their strengths and weaknesses will be evaluated. T2 - Metallomics 2017 CY - Vienna, Austria DA - 14.08.2017 KW - Single cell analysis KW - Laser ablation KW - Nanoparticles KW - ICP-MS PY - 2017 AN - OPUS4-41690 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kaiser, M. A1 - Würth, Christian A1 - Kraft, Marco A1 - Hyppänen, I. A1 - Soukka, T. A1 - Resch-Genger, Ute T1 - Power-dependent upconversion quantum yield of NaYF4:Yb3+,Er3+ nano- and micrometer-sized particles – measurements and simulations N2 - Photophysical studies of nonlinear lanthanide-doped photon upconverting nanoparticles (UCNPs) increasingly used in biophotonics and photovoltaics require absolute measurements of the excitation power density (P)-dependent upconversion luminescence (UCL) and luminescence quantum yields (ΦUC) for quantifying the material performance, UCL deactivation pathways, and possible enhancement factors. We present here the P-dependence of the UCL spectra, ΦUC, and slope factors of the different emission bands of representative 25 nm-sized oleate-capped β-NaYF4:17% Yb3+, 3% Er3+ UCNPs dispersed in toluene and as powder as well as ΦUC of 3 μm-sized upconversion particles (UCμP), all measured with a newly designed integrating sphere setup, enabling controlled variation of P over four orders of magnitude. This includes quantifying the influence of the beam shape on the measured ΦUC and comparison of experimental ΦUC with simulations utilizing the balancing power density model of the Andersson-Engels group and the simulated ΦUC of UCμP from the Berry group, underpinned by closely matching decay kinetics of our UC material. We obtained a maximum ΦUC of 10.5% for UCμP and a ΦUC of 0.6% and 2.1% for solid and dispersed UCNPs, respectively. Our results suggest an overestimation of the contribution of the purple and an underestimation of that of the red emission of β-NaYF4:Yb3+,Er3+: microparticles by the simulations of the Berry group. Moreover, our measurements can be used as a guideline to the absolute determination of UCL and ΦUC KW - Upconversion KW - Photophysics KW - Nanoparticles PY - 2017 DO - https://doi.org/10.1039/c7nr02449e VL - 9 IS - 28 SP - 10051 EP - 10058 PB - The Royal Society of Chemistry AN - OPUS4-41550 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kjaervik, Marit A1 - Dietrich, P. A1 - Thissen, A. A1 - Schwibbert, Karin A1 - Defedov, A. A1 - Wöll, C. A1 - Unger, Wolfgang T1 - Exploring the capabilities of NAP-XPS: Application to metal-organic frameworks, nanoparticles and biofilms N2 - Near-ambient pressure XPS makes it possible to characterise samples not compatible to ultra-high vacuum, and enables the study of liquid-solid, gas-liquid and gas-solid interfaces. NAP-XPS meas-urements of biofilms, suspended nanoparticles and metal-organic frameworks were performed with EnviroESCA developed by SPECS. An interesting application is surface characterisation of biofilms, which are bacterial communities embedded in a self-produced polysaccharide matrix. Various model systems ranging from pure polysaccharides of alginate to biofilms harvested directly from the growth medium have been char-acterised in humid conditions[1]. NAP-XPS also makes it possible to characterise nanoparticles in solution. Silver nanoparticles in aqueous solution were characterised and the Ag 3d-spectrum compared to spectra obtained of dried nanoparticles in UHV-conditions[2]. The binding energy of the Ag 3d-core level peak was shifted by 0,6 eV towards higher binding energy for suspended nanoparticles compared to the dried sample measured in UHV. This can be assigned to a change in surface potential at the water-nanoparticle interface. Metal-organic frameworks (MOFs) are suitable materials for gas storage of small molecules due to their nanoporous, crystalline structure. However, instability in humidity remains an issue for many types of MOFs. XPS-measurements of the MOF-structure HKUST-1 were performed in various NAP-conditions to assess the stability of the sample and its interaction with the gas molecules as water, methanol and pyridine. T2 - 5th AP-XPS Workshop CY - Berlin, Germany DA - 11.12.18 KW - Biofilms KW - E. coli KW - NAP-XPS KW - Metal organic frameworks KW - Nanoparticles PY - 2018 AN - OPUS4-47060 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kjaervik, Marit A1 - Unger, Wolfgang T1 - Exploring the capabilities of near ambient pressure XPS: Characterisation of biofilms and nanoparticles in solution N2 - Seminar-talk for "Ausgewählte analytische Methoden der Physik " at TU Berlin. A introduction about near-ambient pressure XPS is given, furhter, results from measurements of biofilms and dispersed nanoparticles are presented and discussed. T2 - Seminar AG Kanngießer: Ausgewählte analytische Methoden der Physik CY - Technische Universität, Berlin, Germany DA - 04.07.2017 KW - Alginate KW - NAP-XPS KW - Nanoparticles KW - Biofilms KW - E. coli PY - 2017 AN - OPUS4-40905 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kjaervik, Marit A1 - Müller, Anja A1 - Dietrich, P. A1 - Thissen, A. A1 - Bahr, S. A1 - Ritter, B. A1 - Kemnitz, E. A1 - Unger, Wolfgang T1 - Detection of suspended nanoparticles with near-ambient pressure x-ray photoelectron spectroscopy N2 - Two systems of suspended nanoparticles have been studied with near-ambient pressure x-ray photoelectron spectroscopy: silver nanoparticles in water and strontium fluoride—calcium fluoride core-shell nanoparticles in ethylene glycol. The corresponding dry samples were measured under ultra high vacuum for comparison. The results obtained under near-ambient pressure were overall comparable to those obtained under ultra high vacuum, although measuring silver nanoparticles in water requires a high pass energy and a long acquisition time. A shift towards higher binding energies was found for the silver nanoparticles in aqueous Suspension compared to the corresponding dry sample, which can be assigned to a change of surface potential at the water-nanoparticle interface. The shell-thickness of the core-shell nanoparticles was estimated based on simulated spectra from the National Institute of Standards and Technology database for simulation of electron spectra for surface analysis. With the instrumental set-up presented in this paper, nanoparticle suspensions in a suitable Container can be directly inserted into the analysis chamber and measured without prior sample preparation. KW - Nanoparticles KW - Suspensions KW - Core-shell nanoparticles KW - NAP-XPS PY - 2017 DO - https://doi.org/10.1088/1361-648X/aa8b9d SN - 1361-648X SN - 0953-8984 N1 - Geburtsname von Müller, Anja: Hermanns, A. - Birth name of Müller, Anja: Hermanns, A. VL - 29 IS - 47 SP - 474002, 1 EP - 474002, 9 PB - IOP Publishing CY - UK AN - OPUS4-42951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -