TY - CONF A1 - Rurack, Knut T1 - Biomimetically Inspired Sensing of Ionic and Neutral Species with Organically Modified Mesoporous Silica Materials T2 - First International Conference on Multifunctional, Hybrid and Nanomaterials CY - Tours, France DA - 2009-03-15 PY - 2009 AN - OPUS4-19133 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Functional red/NIR dyes and hybrid sensor materials T2 - Working Group Meeting, COST D-31, Working Group 001204 "New Materials for Anion Sensing", School of Chemistry CY - Birmingham, England DA - 2008-01-25 PY - 2008 AN - OPUS4-18547 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rurack, Knut A1 - Martínez-Mánez, Ramon ED - Robert H. Crabtree, T1 - Functional supramolecular hybrid materials N2 - The combination of suitable nanoscopic inorganic supports with supramolecular concepts and bioconjugation strategies opens up exciting perspectives for the development of bioinorganic and organic–inorganic hybrid materials with improved functionalities. Many of the examples from the period 2004 to mid-2007 reviewed here bridge the gap between molecules, materials sciences, biochemistry, and nanotechnology. The synergistic use of these approaches has led to the advancement of various functions such as enhanced recognition, amplified signaling, the controlled assembly and disassembly of aggregates and 3-D architectures. Many of the implemented active functions can be carried out in a reversible and directed fashion on purpose by triggering with an external stimulus. These ideas bring tunability to properties of inorganic solids and new perspectives of application to biochemical and supramolecular concepts. Classic inorganic chemistries such as metal or semiconductor nanoparticles, silica or carbon materials, and coordination chemistry are thus elevated to another level of sophistication and contribute significantly to frontier research areas in directed transport and delivery, nanoelectronics and mechanics, chip technology, smart materials, memory devices, and bioanalytics. KW - Biochemie KW - Biomakromoleküle KW - DNA KW - Gold KW - Hybridmaterialien KW - Nanopartikel KW - Quantenpunkte KW - Selbstorganisation KW - Sensorik KW - Silica KW - Supramolekulare Chemie PY - 2009 DO - https://doi.org/10.1002/0470862106.ia400 SP - 1 EP - 23 PB - Wiley CY - Chichester AN - OPUS4-19847 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - BOOK A1 - Rurack, Knut A1 - Martínez-Mánez, Ramon T1 - Biomimetic chemistry of hybrid materials N2 - The article discusses representative examples published in the field of functional biomimetic chemistry of hybrid materials between 2004 and mid-2007. First, we focus on the modification of morphological aspects of (bio)organic–inorganic hybrid materials to create sophisticated gating and switching mechanisms. The architecture of the systems is presented and the elements of control by external stimuli that have been established in recent years, such as optical, electrochemical, chemical, thermal, or magnetic means, are described. Various functions ranging from (site-specific) delivery to indication at the nanometric level are reported. Next we develop the idea of utilizing hybrid frameworks for biomimetic signaling inspired by the way nature has created binding pockets and the concept of induced-fit. Such a merging of inorganic scaffolds with supramolecular concepts results in enhanced molecular recognition and signaling. Finally selected recent advances in the field of hybrid biomimetic motors both of linear and rotary types are presented. The contribution shows how novel biomimetic functions can arise from synergisms between specifically designed hybrid materials and the implementation of supramolecular and/or bioorganic concepts. KW - Biochemie KW - Biomimetika KW - DNA KW - Gold KW - Hybridmaterialien KW - Molekulare Schalter KW - Molekulare Motoren KW - Nanopartikel KW - Quantenpunkte KW - Schalter KW - Sensorik KW - Silica KW - Supramolekulare Chemie PY - 2009 DO - https://doi.org/10.1002/0470862106.ia420 SP - 1 EP - 20 PB - Wiley CY - Chichester AN - OPUS4-19846 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Development and Application of Particle-based Analytical Platforms for Photo- and Fluorometric Detection T2 - FUTURSEN 2009-Symposium, Universidad Complutense Madrid CY - Madrid, Spain DA - 2009-09-18 PY - 2009 AN - OPUS4-20430 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Biomimetically Inspired Sensing of Ionic and Neutral Species with Organically Modified Mesoporous Silica Materials T2 - First International Conference on Multifunctional, Hybrid and Nanomaterials CY - Tours, France DA - 2009-03-15 PY - 2009 AN - OPUS4-20644 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Red and NIR Polymethinic Dyes and Probes - Prospects, Pitfalls and Latest Developments in Color Rules T2 - Department of Chemistry CY - Valencia, Spain DA - 2009-11-26 PY - 2009 AN - OPUS4-20432 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Radeglia, Reiner A1 - Reck, Günter A1 - Schulz, Burkhard A1 - Resch-Genger, Ute A1 - Bricks, J. A1 - Sonnenschein, H. T1 - Reaction of a N-anthrylcarbonylthiourea derivative with Cu2+ or H+ - unusual rearrangement to a highly fluorescent S-(9-anthryl)-isothiouronium salt N2 - For the fluorescent ligand 1-(9-anthrylcarbonyl)-3,3-tetramethylenethiourea with Cu(ClO4)2 or strong acids an unusual rearrangement reaction occurred yielding a highly emissive S-(9-anthryl)isothiouronium salt. This rearrangement product was characterised by NMR spectroscopy and X-ray analysis as well as absorption and fluorescence spectroscopy. Additionally, the chemical and complexation behaviour of the N-anthrylcarbonylthiourea derivative is compared to that of its naphthyl and phenyl analogues. PY - 2000 DO - https://doi.org/10.1039/b000138o SN - 1472-779X IS - 6 SP - 1209 EP - 1214 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-857 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Resch-Genger, Ute A1 - Pfeifer, Dietmar A1 - Monte, Christian A1 - Pilz, Walter A1 - Hoffmann, Angelika A1 - Spieles, Monika A1 - Rurack, Knut A1 - Hollandt, J. A1 - Taubert, D. A1 - Schönenberger, B. A1 - Nording, P. T1 - Traceability in Fluorometry: Part II. Spectral Fluorescence Standards N2 - The need for the traceable characterization of fluorescence instruments is emphasized from a chemist’s point of view, focusing on spectral fluorescence standards for the determination of the wavelength- and polarization-dependent relative spectral responsivity and relative spectral irradiance of fluorescence measuring systems, respectively. In a first step, major sources of error of fluorescence measurements and instrument calibration are revealed to underline the importance of this issue and to illustrate advantages and disadvantages of physical and chemical transfer standards for generation of spectral correction curves. Secondly, examples for sets of traceable chemical emission and excitation standards are shown that cover a broad spectral region and simple procedures for the determination of corrected emission spectra with acceptable uncertainties are presented. With proper consideration of the respective measurement principle and geometry, these dye-based characterization procedures can be not only applied to spectrofluorometers but also to other types of fluorescence measuring systems and even to Raman spectrometers. KW - Fluorescence KW - Standard KW - Spectral correction KW - Emission KW - Excitation KW - Traceability PY - 2005 DO - https://doi.org/10.1007/s10895-005-2629-9 SN - 1053-0509 SN - 1573-4994 VL - 15 IS - 3 SP - 315 EP - 336 PB - Plenum Publ. Corp. CY - New York, NY AN - OPUS4-10824 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rurack, Knut A1 - Resch-Genger, Ute A1 - Rettig, W. T1 - ZnII and CdII complexes of 2,2'-bipyridyl-3,3'-diol: discrimination with time-resolved fluorometry PY - 1996 SN - 0179-4159 SP - 459 EP - 460 PB - Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung CY - Berlin AN - OPUS4-2102 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kollmannsberger, M. A1 - Rurack, Knut A1 - Resch-Genger, Ute A1 - Daub, J. T1 - Ultrafast charge transfer in amino-substituted boron dipyrromethene dyes and Its inhibition by cation complexation - a new design concept for highly sensitive fluorescent probes N2 - The photophysical behavior of a newly synthesized aza crown-substituted boron-dipyrromethene (BDP) dye and its dimethylamino analogue were investigated with steady-state and time-resolved fluorometry and compared to a reference compound. In solvents more polar than hexane, excitation of the dyes leads to a fast charge transfer from the locally excited (LE) state to a weakly emissive charge-transfer (CT) state. The donor-substituted compounds show dual emission from the LE and CT state, both fluorescence quantum yields being low. The rate constant of excited-state charge separation, calculated from the global analysis of time-resolved emission data, was determined to 1.6 × 1011 s-1 in 1,4-dioxane. The crowned compound forms 1:1-complexes with various alkali and alkaline-earth metal ions, which exist as two conformers in solution. In these complexes, coordination of the cation to the nitrogen donor atom of the crown inhibits the charge-transfer process, leading to a cation-dependent enhancement of the LE emission and the fluorescence lifetimes by factors >103. This efficient "switching on" of the fluorescence renders the crowned BDP dye an extremely sensitive fluorescent probe for metal ions. PY - 1998 DO - https://doi.org/10.1021/jp982701c SN - 1089-5639 SN - 1520-5215 VL - 102 IS - 50 SP - 10211 EP - 10220 PB - Soc. CY - Washington, DC AN - OPUS4-2095 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Rurack, Knut A1 - Bricks, J. A1 - Koval'chuk, A. A1 - Slominskii, J. T1 - Synthesis and Photophysical Properties of Cation-sensitive styryl bases derived from substituted Benzothiazole T2 - 1st All-Russian Conference on Heterocyclic Chemistry CY - Suzdal, Russia DA - 2000-09-19 PY - 2000 SP - 1 AN - OPUS4-858 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - López-Puertollano, Daniel A1 - Duncan, Hadyn A1 - Abad-Somovilla, Antonio A1 - Abad-Fuentes, Antonio A1 - Rurack, Knut T1 - Competitive cytometry-based immunoassay for patulin determination in apple juice N2 - Patulin is a mycotoxin that is frequently found in apples and apple-derived products. Given the potential harm it can cause to humans, maximum levels for patulin in food have been set worldwide. Conventional methods for the detection of patulin are often time-consuming or lack sensitivity. In this study, a novel cytometry approach based on specific monoclonal antibodies is presented. These high-affinity binders do not target patulin itself, but a stable derivative (adduct) that is rapidly obtained in an aqueous medium at room temperature. To develop the assay, a specific fluorescent competitor was designed and synthesized. After optimizing the assay conditions, including the concentration of the fluorescent competitor and of the antibody bound to polystyrene-silica core–shell microparticles, a detection limit of 0.03 μg L-1 in buffer was achieved. Finally, validation according to Commission Regulation (EU) 2023/2782 demonstrated that apple juice samples spiked with patulin at 25 or 50 μg L-1 (permissible limits set by the EU) were properly scored as non-compliant without any additional treatment other than a simple dilution step in buffer. The developed assay offers several key advantages, including rapid analysis, high sensitivity and specificity, and the potential for multiplexing, making it a promising analytical tool for routine monitoring of patulin contamination in food. KW - Bead-based assay KW - Cytometry KW - Derivatization KW - Mycotoxin KW - Patulin PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627659 DO - https://doi.org/10.1016/j.microc.2025.113287 SN - 1095-9149 VL - 212 SP - 1 EP - 8 PB - Elsevier B.V. AN - OPUS4-62765 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - López-Puertollano, Daniel A1 - Tobias, Charlie A1 - Bell, Jérémy A1 - Abad-Somovilla, A. A1 - Abad-Fuentes, A. A1 - Rurack, Knut T1 - Superparamagnetic Bead-Based Microfluidic Fluoroimmunoassay Platform for Rapid Ochratoxin A Detection in Flour N2 - Simplification and reduction of time and costs are the primary goals in the development and use of onsite methods in diagnostics and food safety. To facilitate the transition from laboratory techniques to simple, miniaturized devices, we have developed a modular microfluidic platform. This platform integrates a competitive fluorescence immunoassay on the surface of superparamagnetic beads, serving as a complementary technique to traditional cytometry assays. In the first chip module, a fast competitive reaction (5 min) occurs, after which the particles are retained in the second module. This module consists of a PDMS chip and a permanent magnet, allowing only the fluorescent competitor to reach the detection module. Ochratoxin A (OTA) was chosen as the model analyte for device development, using fluorescein-labeled OTA as a competitor. The system efficiently separates particles, with OTA concentration directly correlated to the amount of fluorescent competitor remaining in solution after the competitive reaction. This innovative setup allows to perform rapid measurements with small sample volumes in a short time (10 min), achieving a limit of detection for OTA of 1.2 μg L–1. The system was successfully applied to the accurate determination of OTA in wheat flour spiked at regulatorily relevant concentrations. Using this device, conventional cytometry immunoassays can be seamlessly transformed into user-friendly, miniaturized analytical methods at reduced cost for applications outside of a laboratory directly at the point of need. KW - Bead-based assay KW - Fluorescence KW - Immunoassay KW - Microfluidics KW - mycotoxins PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638472 DO - https://doi.org/10.1021/acssensors.5c01119 SN - 2379-3694 SP - 1 EP - 10 PB - American Chemical Society CY - Washington, D.C. AN - OPUS4-63847 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yu, Y.-H. A1 - Descalzo López, Ana Belén A1 - Sgen, Z. A1 - Röhr, Holger A1 - Liu, Q. A1 - Wang, Y.-W. A1 - Spieles, Monika A1 - Li, Y.-Z. A1 - Rurack, Knut A1 - You, X.-Z. T1 - Mono- and Di(dimethylamino)styryl-Substituted Borondipyrromethene and Borondiindomethene Dyes with Intense Near-Infrared Fluorescence N2 - Four novel borondipyrromethene (BDP) and -diindomethene (BDI) dyes with one or two (dimethylamino)styryl extensions at the chromophore were synthesized and spectroscopically investigated. An X-ray crystal structure shows that the extended auxochrome is virtually planar. All dyes thus display intense red/near infrared (NIR) absorption and emission. The (dimethylamino)styryl group induces a charge-transfer character that entails bright solvatochromic fluorescence, which is only quenched with increasing solvent polarity according to the energy-gap law. The dye with an additional dimethylanilino group at the meso position of BDP shows a remarkable switching of lipophilicity by protonation. Two dyes with an 8-hydroxyquinoline ligand at the meso position display quenched emission in the presence of Hg2+ or Al3+ owing to electron transfer from the excited BDP to the complexed receptor. The BDI dye presents a pH indicator with bright fluorescence and extremely low fluorescence anisotropy. KW - Borondipyrromethene KW - Dyes KW - Fluorescence KW - Indicators KW - Protonation PY - 2006 DO - https://doi.org/10.1002/asia.200600042 SN - 1861-4728 SN - 1861-471X VL - 1 IS - 1-2 SP - 176 EP - 187 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-12561 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sun, Yijuan A1 - Gawlitza, Kornelia A1 - Valderrey, Virginia A1 - Bell, Jérémy A1 - Rurack, Knut T1 - Polymerizable BODIPY probe crosslinker for the molecularly imprinted polymer-based detection of organic carboxylates via fluorescence N2 - This contribution reports the development of a polymerizable BODIPY-type fluorescent probe targeting small-molecule carboxylates for incorporation into molecularly imprinted polymers (MIPs). The design of the probe crosslinker includes a urea recognition site p-conjugated to the 3-position of the BODIPY core and two methacrylate moieties. Titration experiments with a carboxylate-expressing antibiotic, levofloxacin (LEVO), showed a blue shift of the absorption band as well as a broadening and decrease in emission, attributed to hydrogen bonding between the probe’s urea group and the carboxylate group of the antibiotic. Using this probe crosslinker, core–shell particles with a silica core and a thin MIP shell were prepared for the detection of LEVO. The MIP exhibited highly selective recognition of LEVO, with an imprinting factor of 18.1 compared to the non-imprinted polymer. Transmission electron microscopy confirmed the core–shell structure and spectroscopic studies revealed that the receptor’s positioning leads to a unique perturbation of the polymethinic character of the BODIPY chromophore, entailing the favourable responses. These features are fully preserved in the MIP, whereas no such response was observed for competitors such as ampicillin. The sensory particles allowed to detect LEVO down to submicromolar concentrations in dioxane. We have developed here for the first time a BODIPY probe for organic carboxylates and incorporated it into polymers using the imprinting technique, paving the way for BODIPY-type fluorescent MIP sensors. KW - Fluorescence KW - BODIPY probe KW - Molecularly Imprinted Polymers KW - Sensor Materials KW - Dyes KW - Water analysis KW - Advanced materials PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598629 DO - https://doi.org/10.1039/D3MA00476G SP - 1 EP - 11 PB - Royal Society of Chemistry (RSC) AN - OPUS4-59862 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Verhassel, Alejandra A1 - Kimani, Martha Wamaitha A1 - Gidwani, Kamlesh A1 - Sandholm, Jouko A1 - Gawlitza, Kornelia A1 - Rurack, Knut A1 - Härkönen, Pirkko T1 - Detection of Tn-antigen in breast and prostate cancer models by VVL-labeled red dye-doped nanoparticles N2 - Aim: Fluorescence detection of breast and prostate cancer cells expressing Tn-antigen, a tumor marker, with Vicia villosa lectin (VVL)-labeled nanoparticles. Materials & methods: Breast and prostate cancer cells engineered to express high levels of Tn-antigen and non-engineered controls were incubated with VVL-labeled or unlabeled red dye-doped silica-coated polystyrene nanoparticles. The binding to cells was studied with flow cytometry, confocal microscopy, and electron microscopy. Results: Flow cytometry showed that the binding of VVL-labeled nanoparticles was significantly higher to Tn-antigen-expressing cancer cells than controls. Confocal microscopy demonstrated that particles bound to the cell surface. According to the correlative light and electron microscopy the particles bound mostly as aggregates. Conclusion: VVL-labeled nanoparticles could provide a new tool for the detection of Tn-antigen-expressing breast and prostate cancer cells. KW - Breast cancer cells KW - Fluorescence detection KW - Lectin labeling KW - Prostate cancer cells KW - Silica-coated polystyrene nanoparticles KW - Tn-antigen KW - VVL PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613451 DO - https://doi.org/10.1080/17435889.2024.2405454 SN - 1743-5889 VL - 19 SP - 2463 EP - 2478 PB - Taylor & Francis CY - London AN - OPUS4-61345 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jamieson, O. D. A1 - Bell, Jérémy A1 - Hudson, A. A1 - Saczek, J. A1 - Perez-Padilla, Victor A1 - Kaiya, G. A1 - Novakovic, K. A1 - Davies, M. A1 - Foster, E. A1 - Gruber, J. A1 - Rurack, Knut A1 - Peeters, M. T1 - Design and Application of an Imprinted Polymer Sensor for the Dual Detection of Antibiotic Contaminants in Aqueous Samples and Food Matrices N2 - An innovative polymer-based dual detection microfluidic platform has been developed for the accurate and reliable sensing of trace amounts of antibiotic tetracycline in environmental and food samples. This was achieved through the production of a bespoke polymeric material formed via an imprinting technique using a fluorescent dye. Thus, this enables dual detection of tetracycline, both thermally, via analyzing the heat-transfer resistance at the solid−liquid interface, and optically, through the inner filter effect. The combination of these two methods achieved a nanomolar limit of detection for tetracycline while also providing rapid, selective, and cost-effective sensing. Additionally, this method successfully detected tetracycline levels of 0.56 μM in blank egg samples which was significantly lower than the maximum residual level of 400 μg L−1 (0.9 μM). Our work shows that this approach can be used for the efficient detection of trace antibiotics in complex environmental and food samples, offering enhanced reliability through the integration of two complementary analysis techniques. This sensor has the potential to identify sources of antimicrobial resistance, which is crucial for targeted efforts to combat this pressing global health challenge. KW - Molecularly imprinted polymers KW - Antibiotics monitoring KW - Orthogonal detection KW - Sensors PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626497 DO - https://doi.org/10.1021/acsapm.4c03218 SN - 2637-6105 VL - 7 IS - 4 SP - 1 EP - 9 PB - American Chemical Society CY - Washington, D.C. AN - OPUS4-62649 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhu, Shengchao A1 - Panne, Ulrich A1 - Rurack, Knut T1 - A rapid method for the assessment of the surface group density of carboxylic acid-functionalized polystyrene microparticles N2 - Particle-based assays are becoming versatile analytical tools due to their cost-effectiveness, speed, straightforward and diverse functionalization chemistries, especially when polystyrene particles are used. The introduction of functional groups (–COOH, –NH2, etc.) to the surface of such polystyrene particles promotes their application in bioanalytics. However, the traditional method to determine the amount of surface carboxylate groups is conductivity titration, which is usually time- and resources-consuming and discontinuous. Here, we synthesized polystyrene microparticles with different contents of carboxylate groups, and then investigated a simpler and potentially continuous approach to determine the amount of surface carboxylate groups by Zeta potential measurements. The results were compared to the traditional titration method and to actual coupling efficiencies of the functionalized particles with a model oligonucleotide probe as determined by flow cytometry. All quantification methods revealed good agreement. KW - Konduktometrische Titration KW - Mikropartikel KW - Oberflächenfunktionalisierung KW - Polystyrol KW - Zeta-Potential PY - 2013 DO - https://doi.org/10.1039/c3an36578f SN - 0003-2654 SN - 1364-5528 VL - 138 IS - 10 SP - 2924 EP - 2930 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-28660 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Opel, J. A1 - Hecht, Mandy A1 - Rurack, Knut A1 - Eiblmeier, J. A1 - Kunz, W. A1 - Cölfen, H. A1 - Kellermeier, M. T1 - Probing local pH-based precipitation processes in self-assembled silica-carbonate hybrid materials N2 - Crystallisation of barium carbonate in the presence of silica can lead to the spontaneous assembly of highly complex superstructures, consisting of uniform and largely co-oriented BaCO3 nanocrystals that are interspersed by a matrix of amorphous silica. The formation of these biomimetic architectures (so-called silica biomorphs) is thought to be driven by a dynamic interplay between the components, in which subtle changes of conditions trigger ordered mineralisation at the nanoscale. In particular, it has been proposed that local pH gradients at growing fronts play a crucial role in the process of morphogenesis. In the present work, we have used a special pH-sensitive fluorescent dye to directly trace these presumed local fluctuations by means of confocal laser scanning microscopy. Our data demonstrate the existence of an active region near the growth front, where the pH is locally decreased with respect to the alkaline bulk solution on a length scale of few microns. This observation provides fundamental and, for the first time, direct experimental support for the current picture of the mechanism underlying the formation of these peculiar materials. On the other hand, the absence of any temporal oscillations in the local pH – another key feature of the envisaged mechanism – challenges the notion of autocatalytic phenomena in such systems and raises new questions about the actual role of silica as an additive in the crystallisation process. KW - Silikat-Karbonat-Biomaterialien KW - Self-Assembly KW - Fluoreszenz KW - PH PY - 2015 DO - https://doi.org/10.1039/c5nr05399d SN - 2040-3364 SN - 2040-3372 VL - 7 IS - 41 SP - 17434 EP - 17440 PB - RSC Publ. CY - Cambridge AN - OPUS4-35098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ros-Lis, J.V. A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Soto, J. A1 - Rurack, Knut A1 - Weißhoff, Hardy T1 - Signalling Mechanisms in Anion-Responsive Push-Pull Chromophores: The Hydrogen-Bonding, Deprotonation and Anion-Exchange Chemistry of Functionalized Azo Dyes N2 - A family of azo dyes containing amide (1), urea (2), thiourea (3), carbamate (4) or amino (5) hydrogen-bond donating groups were synthesized and their response toward anions was studied. Acetonitrile solutions of 1-5 show bright yellow colours, due to charge-transfer bands in the 375-400 nm region, slightly modulated by the electron donor strength of the group attached to the 4 end of the 4-nitroazobenzene scaffold. Anions of different shape and size (i.e., spherical F-,Cl-, Br- and I-, planar and tetrahedral oxoanions such as NO3-, H2PO4- and HSO4-, carboxylates such as acetate and benzoate and the linear anions cyanide and thiocyanate) were employed in the recognition studies. Two different effects were distinguished: (i) bathochromic shifts of <40 nm to pale orange, due to anion coordination, and (ii) strong red shifts of ca. 200 nm with a concomitant colour change to blue, due to deprotonation. This behaviour was explained as a balance between the deprotonation tendency of the binding sites in the different receptors and the proton affinities of the anions. Semiempirical calculations were carried out to evaluate the hydrogen bond-donating abilities of the anions and the dyes and a good correlation with the experimentally found values was observed. Stability constants for the receptor-anion complexes were determined spectrophotometrically and the different responses toward fluoride and acetate were assessed by NMR titration experiments. Finally, as a special case, we also report the use of this family of compounds as colorimetric carbon dioxide sensors through reaction with the unprotonated forms of the azo dyes. KW - Chromophores KW - Dyes/Pigments KW - Chemosensors KW - Gas sensors KW - Carbon dioxide PY - 2007 DO - https://doi.org/10.1002/ejoc.200601111 SN - 1434-193X SN - 1099-0690 VL - 2007 IS - 15 SP - 2449 EP - 2458 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-16081 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wagner, R. A1 - Wan, Wei A1 - Biyikal, Mustafa A1 - Benito-Pena, E. A1 - Moreno-Bondi, M.C. A1 - Lazraq, I. A1 - Rurack, Knut A1 - Sellergren, B. T1 - Synthesis, spectroscopic, and analyte-responsive behavior of a polymerizable naphthalimide-based carboxylate probe and molecularly imprinted polymers prepared thereof N2 - A naphthalimide-based fluorescent indicator monomer 1 for the integration into chromo- and fluorogenic molecularly imprinted polymers (MIPs) was synthesized and characterized. The monomer was equipped with a urea binding site to respond to carboxylate-containing guests with absorption and fluorescence changes, namely a bathochromic shift in absorption and fluorescence quenching. Detailed spectroscopic analyses of the title compound and various models revealed the signaling mechanism. Titration studies employing benzoate and Z-ʟ-phenylalanine (Z-ʟ-Phe) suggest that indicator monomers such as the title compound undergo a mixture of deprotonation and complex formation in the presence of benzoate but yield hydrogen-bonded complexes, which are desirable for the molecular imprinting process, with weakly basic guests like Z-ʟ-Phe. Compound 1 could be successfully employed in the synthesis of monolithic and thin-film MIPs against Z-ʟ-Phe, Z-L-glutamic acid, and penicillin G. Chromatographic assessment of the selectivity features of the monoliths revealed enantioselective discrimination and clear imprinting effects. Immobilized on glass coverslips, the thin-film MIPs of 1 displayed a clear signaling behavior with a pronounced enantioselective fluorescence quenching dependence and a promising discrimination against cross-analytes. KW - Aminosäuren KW - Enantioselektivität KW - Fluoreszenz KW - Molekular geprägte polymere KW - Sensorfilme PY - 2013 DO - https://doi.org/10.1021/jo3019522 SN - 0022-3263 SN - 1520-6904 VL - 78 IS - 4 SP - 1377 EP - 1389 PB - American Chemical Society CY - Washington, DC AN - OPUS4-27741 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ros-Lis, J.V. A1 - Martínez-Mánez, Ramon A1 - Soto, J. A1 - Villaescusa, L.A. A1 - Rurack, Knut T1 - Squaraine 'ships' in the Y zeolite 'bottle': a chromogenic sensing material for the detection of volatile amines and thiols N2 - The inclusion of squaraine (SQ) dye I into the supercages of zeolite Y (structure code FAU) with a SiO2/Al2O3 ratio of 30 (Z30) through a two-step ship-in-the-bottle approach is reported, resulting in the squaraine-containing hybrid material Z30-SQ. Attempts to use the same synthetic procedure on sodium and ammonium Y zeolites were unsuccessful, stressing the importance of the presence of Brønsted acid centres in the Z30 zeolite. The reflectance spectra of Z30-SQ show a maximum in the typical squaraine monomer region at 618 nm and a shoulder at 570 nm. Spectral analyses revealed that the major species are SQ dimers and (tightly adsorbed) SQ monomers and SQ aggregates are only formed to a minor degree. The emission spectrum of Z30-SQ shows a single band at 669 nm. The sensory performance of this material was tested in the presence of volatile propylamine and propylthiol and other volatile organic compounds (acetone, ethanol, dichloromethane, hexane, acetonitrile, ethyl acetate, ethyl ether and acetic acid). The blue Z30-SQ material reacts with the thiol and amine derivatives, resulting in the bleaching of the solid and disappearance of the absorption band in the visible region, but does not undergo spectroscopic changes in the presence of other volatile organic compounds (VOCs). Whereas the reaction with propylamine is irreversible, a partial reversibility was found in the presence of the thiol. Theoretical investigations of the reactivity of I with several VOC molecules at the semi-empirical level reproduced well the experimentally observed reactivity. KW - Fluoreszenz KW - Gassensorik KW - Squarain-Farbstoffe KW - Zeolite PY - 2011 DO - https://doi.org/10.1039/c0jm03780j SN - 0959-9428 SN - 1364-5501 VL - 21 IS - 13 SP - 5004 EP - 5010 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-23480 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - PFAS Sensors N2 - This contribution provides an introduction to the development of sensors for PFAS analysis, presents the most common approaches, and describes the opto-microfluidic strategy in combination with polymerizable indicators and detection matrices currently being pursued by the Chemical and Optical Sensing Division at BAM. T2 - Advancements of Analytical Techniques for Per- and Polyfluoroalkyl Substances (PFAS) – Second Workshop 2023 CY - Berlin, Germany DA - 19.09.2023 KW - PFAS KW - Sensors KW - Molecularly imprinted polymers KW - Microfluidics KW - Fluorescence PY - 2023 AN - OPUS4-58533 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kimani, Martha Wamaitha A1 - Kislenko, Evgeniia A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Author correction: Fluorescent molecularly imprinted polymer particles for glyphosate detection using phase transfer agents N2 - This is a corrigendum to the original article "Fluorescent molecularly imprinted polymer particles for glyphosate detection using phase transfer agents" that was published in the journal "Scientific reports", vol. 12 (2022), article no. 14151. PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642416 DO - https://doi.org/10.1038/s41598-023-28025-0 SN - 2045-2322 VL - 13 IS - 1 SP - 1 EP - 2 PB - Macmillan Publishers Limited CY - London AN - OPUS4-64241 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ashokkumar, Pichandi A1 - Bell, Jérémy A1 - Buurman, Merwe A1 - Rurack, Knut T1 - Analytical platform for sugar sensing in commercial beverages using a fluorescent BODIPY "light-up" probe N2 - Because of the globally increasing prevalence of diabetes, the need for accurate, efficient and at best miniaturized automated analytical systems for sugar detection in medical diagnostics and the food industry is still urgent. The development of molecular probes for sugars based on boronic acid receptors offers an excellent alternative to the kinetically slow enzyme-based sugar sensors. Moreover, by coupling such chelating units with dye scaffolds like BODIPYs (boron–dipyrromethenes), highly fluorescent sugar sensing schemes can be realized. In this work, a boronic acid-functionalized BODIPY probe was developed, which binds selectively to fructose’s adjacent diols to form cyclic boronate esters. Placement of an amino group in direct neighborhood of the boronic acid moiety allowed us to obtain a broad working range at neutral pH, which distinguishes the probe from the majority of systems working only at pH > 8, while still meeting the desired sensitivity in the micro-molar range due to a pronounced analyte-induced fluorescence increase. To enhance the applicability of the test in the sense described above, integration with a microfluidic chip was achieved. Here, fructose was selectively detected by fluorescence with similar sensitivity in real time on chip, and an assay for the straightforward detection of sugar in (colored) sodas without sample clean-up was established. KW - BODIPY dyes KW - Boronic acid KW - Fluorescence KW - Microfluidics KW - Sugars PY - 2018 DO - https://doi.org/10.1016/j.snb.2017.09.201 SN - 0925-4005 VL - 256 SP - 609 EP - 615 PB - Elsevier CY - Amsterdam AN - OPUS4-43102 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Descalzo, Ana B. A1 - Xu, H.-J. A1 - Shen, Z. A1 - Rurack, Knut T1 - Influence of the meso-substituent on strongly red emitting phenanthrene-fused boron–dipyrromethene (BODIPY) fluorophores with a propeller-like conformation N2 - Highly emissive phenanthrene-fused boron–dipyrromethene (PBDP) dyes have been spectroscopically characterized in a series of solvents. The influence of different substituents (-H, -I, -CN, -DMA or a 15C5-crown ether) in the para-position of a phenyl ring attached to the meso-position of the BODIPY core is discussed. This family of dyes has an intense emission at lambda > 630 nm, with fluorescence quantum yields between 0.7 and 1.0 in all solvents studied, except in the case of the dimethylamino-substituted derivative, PBDP-DMA, which undergoes excited-state intramolecular charge transfer (CT), leading to broadband dual fluorescence in highly polar solvents. Introduction of a weaker electron donor such as a benzocrown to the meso-position is not able to trigger a second (charge or electron transfer) process and, interestingly, heavy atom (iodine, PBDP-I derivative) substitution at that moiety does also not have a relevant influence on the photophysics, i.e., enhanced intersystem crossing was not observed. Electrochemical studies of PBDP-DMA complement the data reported and stress the fact that the decrease in fluorescence of PBDP-DMA in highly polar solvents is due to an excited-state CT process rather than to a photoinduced electron transfer (PET). KW - BODIPY dyes KW - Charge transfer KW - Fluorescence KW - Ring fusion PY - 2018 DO - https://doi.org/10.1016/j.jphotochem.2017.10.034 SN - 1010-6030 VL - 352 SP - 98 EP - 105 PB - Elsevier CY - Amsterdam AN - OPUS4-43100 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Empowering test strips for rapid, highly sensitive and multiplexed analysis of small molecule analytes at a point-of-need N2 - In particular, the rapid development of lateral flow assays as indispensable tools for everyone to contain the SARS-CoV-2 pandemic has fuelled the global demand for analytical tests that can be used outside dedicated laboratories. In addition to their use in medical diagnostics, rapid tests and assays have become increasingly important in various fields such as food safety, security, forensics, and environmental management. The advantage is obvious: taking the assay directly to the sample minimizes the time between suspicion and decision-making, allowing faster action. Especially today, when mobile communication devices with powerful computing capabilities and built-in cameras are ubiquitous, more people than ever before around the world have the basic skills to operate a powerful detector at their fingertips. This sets the stage for a much wider use of analytical measurements in terms of prognosis and prevention, enabling professional laypersons in particular. However, current strip-based systems are primarily focused on single parameter analysis, whether it is SARS-CoV-2 biomarkers, blood glucose levels, or lead concentrations in water samples. Industrial applications of such methods also often still rely on single-parameter assays, requiring multiple runs even for a limited number of key parameters. Overcoming these limitations depends on developing low-number multiplexing strategies that ensure robustness, reliability, speed, ease of use, and sensitivity. This lecture will give an overview of several generic approaches developed in recent years to address these challenges. It will highlight how the synergy 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.1-5 Selected examples will introduce key aspects of such systems that include tailored signaling mechanisms and recognition elements, materials functionalization and device integration, including hybrid nanomaterials, gated indicator release systems, strip modification, and smartphone-based analysis. T2 - 15th Rapid Methods Europe Conference CY - Amsterdam, Netherlands DA - 06.11.2023 KW - Test strips KW - Lateral flow assays KW - Explosives KW - Pesticides KW - Rapid testing KW - Multiplexing PY - 2023 AN - OPUS4-58816 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Chips or strips – the importance of embedding and integration in (bio)chemical assay development N2 - The most important aspect of developing a miniaturized or compact (bio)chemical assay for use outside a dedicated laboratory environment is, of course, the design of the recognition and signaling element that best achieves the required selectivity and sensitivity in relation to the target analyte and analytical scenario. For luminescence assays, this essentially means that the appropriate combination of small-molecule binding units, ligands or biomacromolecular binders such as antibodies or aptamers and organic, metal-organic or rare earth metal ion luminophores or luminescent nanoparticles such as semiconductor nanocrystals, carbon nanodots, polymer dots or fluorescently doped silica or polymer nanoparticles as well as the best strategy for combining binding and signaling unit must be selected. Having accomplished this task and obtained first promising results in a conventional laboratory setting with the use of pipettes, cuvettes and benchtop spectrometers, the challenge is to bridge the gap between such a model assay and an assay that uses a mobile and robust device in the hands of a layperson and does not require complicated operation and extensive manual steps, especially when handling liquids, at best in line with the ASSURED principle, being affordable, sensitive, specific, user-friendly, rapid and robust, equipment free and deliverable to end-users, or, as recently proposed, the REASSURED principle, which furthermore includes real-time connectivity and ease of specimen collection (translating into ease of sampling in the non-diagnostic world). In order to close this gap, it is of utmost importance to know the further requirements of the assay, i.e., whether only one or more than one analyte needs to be detected, what the main potential interferents are and how tolerant the assay is to the sample matrix, as well as how many assays are typically performed per hour/day/week, how long a run should take and how expensive a single analysis should be. These parameters usually determine the most appropriate format, i.e., whether it is a dip stick, a test strip, a lateral flow assay, a microfluidic chip, a 3D-microfluidic approach or a combination thereof, in conjunction with a dedicated readout system or a mobile communication device. This choice in turn determines the most appropriate strategy for integration, i.e., whether the recognition and signaling element are used directly in liquid solution,8 embedded in polymer layers or gels, attached to surfaces of planar substrates, micro- or nanoparticles or immobilized or loaded in micro- or nanoparticles, which could then enable direct or controlled/gated access. This contribution discusses various aspects of this multi-stage process using examples from the group. T2 - How to develop a sensor? Academic Approaches vs. Industrial Interests (EU Training School) CY - Kaiserslautern, Germany DA - 18.09.2024 KW - Sensing KW - Rapid testing KW - Microfluidics KW - Test strips KW - Device integration PY - 2024 AN - OPUS4-61429 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Biyikal, Mustafa A1 - Rurack, Knut T1 - Development of a Lab-on-a-Chip for the Detection of Nerve Agents with a Handheld Device N2 - The development of a Lab-on-a-Chip (LoC) is presented, which can detect reactive phosphorous compounds in the gas phase in combination with an optochemical hand-held sensor. The LoC prototype contains three pairs of sensing materials containing fluorescent indicator dyes in various carrier materials. By measuring the fluorescence response to phosphoryl chloride, a surrogate compound, the detection of chemical warfare agents (CWAs) in gas phase becomes possible within seconds, introducing a novel approach to CWA detection. T2 - 2023 IEEE SENSORS Conference CY - Vienna, Austria DA - 29.10.2023 KW - Lab-on-a-Chip KW - Nerve agents KW - Hand-held KW - Fluorescence KW - Toxic industrial chemicals PY - 2023 UR - https://ieeexplore.ieee.org/document/10325263 SN - 979-8-3503-0387-2 DO - https://doi.org/10.1109/SENSORS56945.2023.10325263 SP - 1 EP - 4 PB - IEEE CY - New York AN - OPUS4-59367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Integrating BODIPY Probes with Devices for On-site Sensing Applications N2 - The detection of potential contaminants as early as possible and as close to their point of emission as well as immission is becoming increasingly important in contemporary environmental analytical chemistry. In addition, real-time monitoring of important chemical parameters for process control is strongly gaining relevance within the context of Industry 4.0. Not only is the development of powerful optical probes thus necessary but also their integration into a matrix and/or device that allows for the application of such systems in realistic measurement scenarios. Integrating fluorescent probes with sensing matrices, however, presents a major challenge because usually, when confined in a rather rigid matrix, fluorophores tend to behave completely different than for instance in the molecular state in solution. The present contribution will highlight recent examples of successful integration of BODIPY (boron–dipyrromethene) based probes with devices that have been developed in our group. A simple system utilizing a test strip for direct readout with a conventional miniaturized camera as for instance routinely used in smartphones was recently devised by us for the determination of organophosphate nerve or chemical warfare agents (CWAs) Sarin (GB), Soman (GD), and Tabun (GA) in aqueous environments. Here, we coupled a reactive BODIPY to the inner and outer surface of mesoporous silica nanoparticles. In the presence of CWAs, the reactive BODIPY dye with an optimally positioned hydroxyl group undergoes an acylation reaction, yielding a bicyclic product that is non-emissive. The strong fluorescence quenching response allows reaching LODs in the pM range in natural waters. Steric embedding, again relying on test strip analysis in combination with a smartphone-based readout and data processing, was sufficient to create a reusable optical pH stick. The family of pH-responsive fluorescent BODIPY probes used for this purpose has been designed in a rational manner with the aid of quantum chemistry tools. All the probes display very similar spectroscopic properties with ON−OFF fluorescence switching responses, being retained after embedding of the probes into hydrogel sensor spots on a plastic strip. Dispensing with a matrix yet invoking microfluidic chips finally permits to use a highly sensitive boronic acid-functionalized BODIPY probe for in-line sugar analysis for instance in the beverage industry. Placement of an amino group in direct neighbourhood of the boronic acid moiety yielded a broad working range at neutral pH while meeting the desired sensitivity in the micro-molar range due to a pronounced analyte-induced fluorescence increase, guaranteeing the straightforward detection of sugar in (coloured) sodas without sample clean-up. T2 - 10th International Conference on Porphyrins & Phthalocyanines CY - Munich, Germany DA - 01.06.2018 KW - BODIPY dyes KW - Nerve agents KW - PH KW - Sugars KW - Devices KW - Fluorescence sensing PY - 2018 AN - OPUS4-45642 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hecht, Mandy A1 - Climent Terol, Estela A1 - Biyikal, Mustafa A1 - Sancenón, F. A1 - Martínez-Mánez, Ramon A1 - Rurack, Knut T1 - Gated hybrid delivery systems: En route to sensory materials with inherent signal amplification N2 - Hybrid nanoparticles with a large specific surface area are a particularly exciting vehicle for delivery applications. Such highly porous or container-like structures, usually prepared from silica and frequently from gold, can incorporate a large number of chemical substances such as drug and/or indicator molecules. When equipped with a chemically or physically addressable gating function at the openings of the voids, the release of the cargo can be controlled at will. Because many more molecules can be stored as cargo in the pores of the support than there are functional groups as anchoring sites for the gating entities attached to the outer surface (for efficient pore capping), the systems possess inherent features of (signal) amplification. The present article will introduce various design strategies for different types of physical (light, temperature, magnetism) and chemical (pH, metal ions, anion, small organic molecules, enzymes) stimuli in connection with drug and indicator release. We will highlight exciting aspects of combining both features in theranostic applications and will stress which requirements still have to be met by many of the systems to be readily applicable in a sensory context. KW - Delivery systems KW - Hybrid materials KW - Molecular gates KW - Sensing KW - Theranostics KW - Freisetzungssysteme KW - Hybridmaterialien KW - Molekulare Gatter KW - Sensorik KW - Theranostik PY - 2013 DO - https://doi.org/10.1016/j.ccr.2013.03.020 SN - 0010-8545 VL - 257 IS - 17-18 SP - 2589 EP - 2606 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-28940 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhu, Shengchao A1 - Fischer, Tobias A1 - Wan, Wei A1 - Descalzo López, Ana Belén A1 - Rurack, Knut T1 - Luminescence amplification strategies integrated with microparticle and nanoparticle platforms N2 - The amplification of luminescence signals is often the key to sensitive and powerful detection protocols. Besides optimized fluorescent probes and labels, functionalized nano- and microparticles have received strongly increasing attention in this context during the past decade. This contribution introduces the main signalling concepts for particle-based amplification strategies and stresses, especially the important role that metal and semiconductor nanoparticles play in this field. Besides resonance energy transfer, metal-enhanced emission and the catalytic generation of luminescence, the impact of multi-chromophoric objects such as dye nanocrystals, dendrimers, conjugated polymers or mesoporous hybrid materials is assessed. The representative examples discussed cover a broad range of analytes from metal ions and small organic molecules to oligonucleotides and enzyme activity. KW - Luminescence KW - Multi-chromosphore systems KW - Nanoparticles KW - Resonance energy transfer KW - Signal amplification PY - 2011 DO - https://doi.org/10.1007/128_2010_99 SN - 0340-1022 SN - 1436-5049 VL - 300 SP - 51 EP - 91 PB - Springer CY - Berlin ; Heidelberg [u.a.] AN - OPUS4-23633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ashokkumar, Pichandi A1 - Rurack, Knut T1 - Fluor on Tour - Schnelltests für die Fluorid-Bestimmung in Wasser N2 - Fluorid-Zusatz zum Trinkwasser oder Zahncreme ist weit verbreitet und dient vor allem der Zahngesundheit und als vorbeugende Maßnahme gegen Knochenkrankheiten. Doch eine zu hohe Konzentration an Fluorid kann zu gesundheitlichen Problemen führen. Der hier in diesem Artikel vorgestellte Farbschnelltest kann helfen, die Fluoridkonzentration leichter festzustellen. KW - Fluorid KW - Fluoreszenz KW - Schnelltest KW - Teststreifen-Assay KW - Wasser PY - 2014 UR - http://www.git-labor.de/forschung/chemie-physik/fluor-tour SN - 0016-3538 VL - 7 SP - 30 EP - 33 PB - GIT-Verlag CY - Darmstadt AN - OPUS4-32013 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Descalzo López, Ana Belén A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Hoffmann, Katrin A1 - Rurack, Knut T1 - Die supramolekulare Chemie organisch-anorganischer Hybrid-Nanomaterialien N2 - Die Entwicklung von Hybridmaterialien mit stark verbesserten Funktionen gelingt durch die Kombination geeigneter Nanomaterialien als Träger mit Motiven aus der supramolekularen Chemie. Diese hetero-supramolekularen Konzepte bieten vielfältige Möglichkeiten, die Lücken zwischen der Molekülchemie, Materialwissenschaften und Nanotechnologie zu schließen. Im Hinblick auf funktionelle Aspekte wurden in jüngster Zeit wichtige Fortschritte erzielt, z. B. verbesserte Erkennungs- und Sensoreigenschaften durch die Anordnung von Molekülen auf vororganisierten Oberflächen, der reversible Aufbau von nanometergroßen Netzwerken und dreidimensionalen Strukturen oder biomimetische und gesteuerte chemische Prozesse in Hybrid-Nanomaterialien, die als Grundlage für hoch spezialisierte Protokolle in dreidimensionalen Gerüststrukturen dienen können. Diese Ansätze ermöglichen eine Feinabstimmung der Eigenschaften von Nanomaterialien und eröffnen neue Perspektiven für die Anwendung supramolekularer Konzepte. KW - Supramolekulare Chemie KW - Anorganisch-organische Hybridmaterialien KW - Sensorik KW - Molekulare Maschinen KW - Aggregation KW - Mesoporöse Materialien KW - Molekulare Erkennung KW - Nanopartikel KW - Sensoren PY - 2006 DO - https://doi.org/10.1002/ange.200600734 SN - 0044-8249 SN - 0932-2140 SN - 1521-3757 VL - 118 IS - 36 SP - 6068 EP - 6093 PB - Wiley-VCH CY - Weinheim AN - OPUS4-12821 LA - deu 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 - Descalzo López, Ana Belén A1 - Hoffmann, Katrin A1 - Rurack, Knut A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. T1 - Hybridmaterialien in der analytischen Chemie KW - Analytische Chemie KW - Hybridmaterialien KW - Sensorik KW - Fluoreszenz KW - Absorption KW - Mesoporöse Silicate KW - Goldnanopartikel KW - Quantenpunkte PY - 2007 SN - 1439-9598 SN - 1521-3854 VL - 55 IS - 02 SP - 124 EP - 129 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-16080 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wagner, Sabine A1 - Bell, Jérémy A1 - Biyikal, Mustafa A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Integrating fluorescent molecularly imprinted polymer (MIP) sensor particles with a modular microfluidic platform for nanomolar smallmolecule detection directly in aqueous samples N2 - Fluorescent sensory MIP (molecularly imprinted polymer) particles were combined with a droplet-based 3D microfluidic system for the selective determination of a prototype small-molecule analyte of environmental concern, 2,4-dichlorophenoxyacetic acid or 2,4-D, at nanomolar concentration directly in water samples. A tailor-made fluorescent indicator cross-linker was thus designed that translates the binding event directly into an enhanced fluorescence signal. The phenoxazinone-type cross-linker was co-polymerized into a thin MIP layer grafted from the surface of silica microparticles following a RAFT (reversible addition-fragmentation chain transfer) polymerization protocol. While the indicator cross-linker outperformed its corresponding monomer twin, establishment of a phase-transfer protocol was essential to guarantee that the hydrogen bond-mediated signalling mechanism between the urea binding site on the indicator cross-linker and the carboxylate group of the analyte was still operative upon real sample analysis. The latter was achieved by integration of the fluorescent core-shell MIP sensor particles into a modular microfluidic platform that allows for an in-line phasetransfer assay, extracting the analyte from aqueous sample droplets into the organic phase that contains the sensor particles. Real-time fluorescence determination of 2,4-D down to 20 nM was realized with the system and applied for the analysis of various surface water samples collected from different parts of the world. KW - Molecular imprinting KW - Microfluidics KW - Fluorescence KW - Core-shell particles KW - Droplets PY - 2018 DO - https://doi.org/10.1016/j.bios.2017.07.053 SN - 0956-5663 VL - 99 IS - 1 SP - 244 EP - 250 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-42258 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mansurova, Maria A1 - Gotor, Raúl A1 - Johann, Sergej A1 - Neumann, Patrick P. A1 - Bartholmai, Matthias A1 - Rurack, Knut A1 - Bell, Jérémy T1 - Fluorescent Hydrophobic Test Strips with Sterically Integrated Molecular Rotors for the Detection of Hydrocarbons in Water and Soil with an Embedded Optical Read-Out N2 - Contamination of natural bodies of water or soil with oils and lubricants (or generally, hydrocarbon derivatives such as petrol, fuels, 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 (TPHs) in water and soil. The test is based on the measurement of the fluorescence signal emitted by the molecular rotor 2-[ethyl[4-[2-(4-nitrophenyl)ethenyl]phenyl]amino]ethanol (4-DNS-OH). This dye is embedded in a hydrophobic polymeric matrix (polyvinylidene fluoride), avoiding interactions with water and providing a robust support for use in a test strip fashion. Together with the strips, an embedded optical system was designed for fluorescence signal read-out, featuring a Bluetooth low-energy connection to a commercial tablet device for data processing and analysis. This system works for the detection and quantification of TPHs in water and soil through a simple extraction protocol using a cycloalkane solvent with a limit of detection of 6 ppm. Assays in surface and sea waters were conclusive, proving the feasibility of the method for in-the-field operation. KW - Test strip KW - Sensor KW - Smartphone KW - Fluorescence KW - Test Streifen KW - Sensoren KW - Fluoreszenz KW - Petrol KW - Öl PY - 2023 DO - https://doi.org/10.1021/acs.energyfuels.3c01175 SN - 0887-0624 SP - 1 EP - 6 PB - American Chemical Society CY - Washington, United States AN - OPUS4-57892 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Sensitive and multiplexed assays for point-of-need applications: innovations for robust, reliable, and user-friendly diagnostics N2 - The development of portable analytical assays, particularly during the SARS-CoV-2 pandemic, has revolutionized diagnostics and expanded their use to areas such as food safety, environmental monitoring and forensics. These assays offer the advantage of rapid on-site decision making without the need for laboratory facilities. The omnipresence of mobile devices with advanced cameras and processing power further increases their usability. However, most current assays are limited to detecting single parameters. The challenge now is to develop robust multiplexed assays that can simultaneously detect multiple parameters with high sensitivity. This lecture will present generic approaches developed at BAM with a focus on supramolecular chemistry, luminescence detection, nanomaterials and miniaturization of devices. Examples include mesoporous nanomaterials, gated indicator systems, imprinted polymers, microfluidic devices, test strips and smartphone-based analysis. T2 - Kolloquium Optische Technologien der FH Münster CY - Steinfurt, Germany DA - 18.12.2024 KW - Rapid testing KW - Fluorescence KW - Explosives KW - Environmental contaminants KW - Multiplexing PY - 2024 AN - OPUS4-62322 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Climent Terol, Estela A1 - Biyikal, Mustafa A1 - Gawlitza, Kornelia A1 - Dropa, T. A1 - Urban, M. A1 - Costero, A. M. A1 - Martínez-Mánez, Ramon A1 - Rurack, Knut T1 - Determination of the chemical warfare agents Sarin, Soman and Tabun in natural waters employing fluorescent hybrid silica materials N2 - A novel mesoporous silica material containing boron–dipyrromethene (BODIPY) moieties (I) is employed for the detection of nerve agent simulants (NASs) and the organophosphate nerve or chemical warfare agents (CWAs) Sarin (GB), Soman (GD), and Tabun (GA) in aqueous environments. The reactive BODIPY dye with an optimum positioned hydroxyl group undergoes acylation reactions with phosph(on)ate substrates, yielding a bicyclic ring. Due to aggregation of the dyes in water, the sensitivity of the free dye in solution is very low. Only after immobilization of the BODIPY moieties into the silica substrates is aggregation inhibited and a sensitive determination of the NASs diethyl cyanophosphonate (DCNP), diethyl chlorophosphate (DCP) and diisopropyl fluorophosphate (DFP) possible. The signaling mode is a strong quenching of the fluorescence, reaching LODs in the pM range. The best performing hybrid material was singled out from a library of hybrid silicas varying in morphology and surface functionalization. The response to actual CWAs such as GB, GD, and GA has also been tested, offering similar behavior as for the simulants. The proposed reaction mechanism has been verified by investigation of other model materials, containing for instance BODIPY moieties without an optimum hydroxyl group (III) or a BODIPY dye with an all-aliphatic counterpart (IV). The latter can only form a monocyclic reaction product, showing much less reactivity as I. Assays with other possible competitors have been additionally carried out, showing favorably low cross-reactivities. Finally, the determination of NASs in several natural waters has been demonstrated. KW - Nerve agent simulants KW - Mesoporous silica materials KW - Fluorescence detection PY - 2017 UR - http://www.sciencedirect.com/science/article/pii/S0925400517303428 DO - https://doi.org/10.1016/j.snb.2017.02.115 SN - 0925-4005 VL - 246 SP - 1056 EP - 1065 PB - Elsevier B.V. AN - OPUS4-39739 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wan, Wei A1 - Biyikal, Mustafa A1 - Wagner, R. A1 - Sellergren, B. A1 - Rurack, Knut T1 - Fluorescent sensorymicroparticles that 'light-up' consisting of a silica core and a molecularly imprinted polymer (MIP) shell N2 - From darkness came light: Incorporation of urea-based fluorescent dyes in an anion-imprinted thin polymer shell coated onto silica microparticles leads to a unique and highly enantioselective fluorescent 'light-up' response to analytes (see scheme, MIP molecularly imprinted polymer). KW - Core–shell particles KW - Enantioselectivity KW - Fluorescence KW - Molecularly imprinted polymers KW - Sensors PY - 2013 DO - https://doi.org/10.1002/anie.201300322 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 52 IS - 27 SP - 7023 EP - 7027 PB - Wiley-VCH CY - Weinheim AN - OPUS4-28740 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Brita A1 - Rurack, Knut A1 - Müller, Ralf A1 - Jancke, Harald T1 - Untersuchungen zur Alterung von Kieselsolen und -gelen T2 - 11. Arbeitstagung des AK Nichtkristalline und Partiellkristalline Strukturen CY - Wolfersdorf, Deutschland DA - 2003-09-08 PY - 2003 UR - http://www2.uni-jena.de/chemie/DGK-AK4/VOR_03/Unger.pdf SP - 1(?) EP - 10(?) AN - OPUS4-3119 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Giménez, C. A1 - Climent Terol, Estela A1 - Aznar, E. A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Marcos, D. A1 - Amorós, P. A1 - Rurack, Knut T1 - Towards chemical communication between gated nanoparticles N2 - The design of comparatively simple and modularly configurable artificial systems able to communicate through the exchange of chemical messengers is, to the best of our knowledge, an unexplored field. As a proof-of-concept, we present here a family of nanoparticles that have been designed to communicate with one another in a hierarchical manner. The concept involves the use of capped mesoporous silica supports in which the messenger delivered by a first type of gated nanoparticle is used to open a second type of nanoparticle, which delivers another messenger that opens a third group of gated nanoobjects. We believe that the conceptual idea that nanodevices can be designed to communicate with one another may result in novel applications and will boost further advances towards cooperative systems with complex behavior as a result of the communication between simple abiotic individual components. KW - Chemical communication KW - Gated nanoparticles KW - Mesoporous materials KW - Nanoparticles community KW - Nanoparticles PY - 2014 DO - https://doi.org/10.1002/anie.201405580 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 53 IS - 46 SP - 12629 EP - 12633 PB - Wiley-VCH CY - Weinheim AN - OPUS4-32136 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - BOOK A1 - Rurack, Knut A1 - Martínez-Mánez, Ramon T1 - Hybrid (nano)materials meet supramolecular chemistry: A brief introduction to basic terms and concepts KW - Hybridmaterialien KW - Nanopartikel KW - Selbstorganisation KW - Supermolekulare Chemie PY - 2010 SN - 978-0-470-37621-8 SP - 1 EP - 10 PB - John Wiley & Sons CY - Hoboken, New Jersey, USA AN - OPUS4-21959 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Particle-based Hybrid Sensor Materials for Photo- and Fluorometric Detection T2 - Molecular Sensors and Molecular Logic Gates (MSMLG-2010) CY - Antalya, Turkey DA - 2010-10-22 PY - 2010 AN - OPUS4-22868 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wan, Wei A1 - Biyikal, Mustafa A1 - Wagner, R. A1 - Sellergren, B. A1 - Rurack, Knut T1 - Sensorische Mikropartikel aus einem Silicatkern und einem molekular geprägten Polymer als Schale mit aufleuchtender Fluoreszenz N2 - Und es ward Licht – der Einbau eines auf Harnstoff basierenden Fluoreszenzfarbstoffs in eine mit Anionen geprägte dünne Polymerschale (MIP) auf Silicatmikropartikeln führt zu einem spezifischen und enantioselektiven Aufleuchten der Fluoreszenz in Gegenwart des Zielanalyten. KW - Enantioselektivität KW - Fluoreszenz KW - Kern-Schale-Partikel KW - Molekular geprägte Polymere KW - Sensoren PY - 2013 DO - https://doi.org/10.1002/ange.201300322 SN - 0044-8249 SN - 0932-2140 SN - 1521-3757 VL - 125 IS - 27 SP - 7161 EP - 7165 PB - Wiley-VCH CY - Weinheim AN - OPUS4-28739 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rurack, Knut A1 - Martínez-Mánez, Ramon ED - Charles M. Lukehart, ED - Robert A. Scott, T1 - Functional Supramolecular Hybrid Materials N2 - The combination of suitable nanoscopic inorganic supports with supramolecular concepts and bioconjugation strategies opens up exciting perspectives for the development of bioinorganic and organic–inorganic hybrid materials with improved functionalities. Many of the examples from the period 2004 to mid-2007 reviewed here bridge the gap between molecules, materials sciences, biochemistry, and nanotechnology. The synergistic use of these approaches has led to the advancement of various functions such as enhanced recognition, amplified signaling, the controlled assembly and disassembly of aggregates and 3-D architectures. Many of the implemented active functions can be carried out in a reversible and directed fashion on purpose by triggering with an external stimulus. These ideas bring tunability to properties of inorganic solids and new perspectives of application to biochemical and supramolecular concepts. Classic inorganic chemistries such as metal or semiconductor nanoparticles, silica or carbon materials, and coordination chemistry are thus elevated to another level of sophistication and contribute significantly to frontier research areas in directed transport and delivery, nanoelectronics and mechanics, chip technology, smart materials, memory devices, and bioanalytics. KW - Biochemie KW - Biomakromoleküle KW - DNA KW - Gold KW - Hybridmaterialien KW - Nanopartikel KW - Quantenpunkte KW - Selbstorganisation KW - Sensorik KW - Silica KW - Supramolekulare Chemie PY - 2008 SN - 978-0470-51644-7 SP - 789 EP - 812 PB - Wiley CY - Chichester AN - OPUS4-19212 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Biyikal, Mustafa A1 - Hecht, Mandy A1 - Rurack, Knut T1 - Mimicking tricks from nature with sensory organic-inorganic hybrid materials N2 - Design strategies for (bio)chemical systems that are inspired by nature's accomplishments in system design and operation on various levels of complexity are increasingly gaining in importance. Within the broad field of biomimetic chemistry, this article highlights various attempts toward improved and sophisticated sensory materials that rely on the combination of supramolecular (bio)chemical recognition principles and nanoscopic solid structures. Examples range from more established concepts such as hybrid sensing ensembles with improved sensitivity and selectivity or for target analytes for which selectivity is hard to achieve by conventional methods, which were often inspired by protein binding pockets or ion channels in membranes, to very recent approaches relying on target-gated amplified signalling with functionalised mesoporous inorganic supports and the integration of native biological sensory species such as transmembrane proteins in spherically supported bilayer membranes. Besides obvious mimicry of recognition-based processes, selected approaches toward chemical transduction junctions utilizing artificially organized synapses, hybrid ensembles for improved antibody generation and uniquely colour changing systems are discussed. All of these strategies open up exciting new prospects for the development of sensing concepts and sensory devices at the interface of nanotechnology, smart materials and supramolecular (bio)chemistry. KW - Sensorik KW - Supramolekulare Chemie KW - Biomimetik KW - Nanotechnologie KW - Hybridmaterialien PY - 2011 DO - https://doi.org/10.1039/c1jm11210d SN - 0959-9428 SN - 1364-5501 VL - 21 IS - 34 SP - 12588 EP - 12604 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-24352 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ros-Lis, J.V. A1 - Casasús, R. A1 - Comes, M. A1 - Coll, C. A1 - Marcos, M. Dolores A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Soto, J. A1 - Amorós, P. A1 - El Haskouri, J. A1 - Garró, N. A1 - Rurack, Knut T1 - A mesoporous 3D hybrid material with dual functionality for Hg2+ detection and adsorption KW - Dyes/pigments KW - Environmental chemistry KW - Mercury KW - Mesoporous materials KW - Sensors PY - 2008 DO - https://doi.org/10.1002/chem.200800632 SN - 0947-6539 SN - 1521-3765 VL - 14 SP - 8267 EP - 8278 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-18443 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rurack, Knut A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Descalzo López, Ana Belén ED - Rurack, Knut ED - Martínez-Mánez, Ramon T1 - Biomimetically inspired signaling KW - Bindungstaschen KW - Biochemie KW - Biomimetika KW - Chromatophore KW - Gold KW - Hybridmaterialien KW - Ionenkanäle KW - Metalloregulation KW - Nanopartikel KW - Quantenpunkte KW - Sensorik KW - Silica KW - Supramolekulare Chemie KW - Verdrängungsassays PY - 2010 SN - 978-0-470-37621-8 SP - 549 EP - 580 PB - John Wiley & Sons CY - Hoboken, New Jersey, USA AN - OPUS4-21960 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beer, G. A1 - Rurack, Knut A1 - Daub, J. T1 - Chiral discrimination with a fluorescent boron-dipyrromethane dye PY - 2001 DO - https://doi.org/10.1039/b102376b SN - 0022-4936 SN - 0009-241x SN - 1359-7345 SN - 1364-548x SP - 1138 EP - 1139 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-2085 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rurack, Knut A1 - Rettig, W. T1 - Different binding modes of ZnII and CdII complexes of 2,2'-bipyridyl-3,3'-diol: evidence by time-resolved fluorometry PY - 2000 SN - 0179-4159 SP - 166 EP - 167 PB - Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung CY - Berlin AN - OPUS4-2094 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tobias, Charlie A1 - Climent Terol, Estela A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Polystyrene Microparticles with Convergently Grown Mesoporous Silica Shells as a Promising Tool for Multiplexed Bioanalytical Assays N2 - Functional core/shell particles are highly sought after in analytical chemistry, especially in methods suitable for single-particle analysis such as flow cytometry because they allow for facile multiplexed detection of several analytes in a single run. Aiming to develop a powerful bead platform of which the core particle can be doped in a straightforward manner while the shell offers the highest possible sensitivity when functionalized with (bio)chemical binders, polystyrene particles were coated with different kinds of mesoporous silica shells in a convergent growth approach. Mesoporous shells allow us to obtain distinctly higher surface areas in comparison with conventional nonporous shells. While assessing the potential of narrow- as well as wide-pore silicas such as Mobil composition of matter no. 41 (MCM-41) and Santa Barbara amorphous material no. 15 (SBA-15), especially the synthesis of the latter shells that are much more suitable for biomolecule anchoring was optimized by altering the pH and both, the amount and type of the mediator salt. Our studies showed that the best performing material resulted from a synthesis using neutral conditions and MgSO4 as an ionic mediator. The analytical potential of the particles was investigated in flow cytometric DNA assays after their respective functionalization for individual and multiplexed detection of short oligonucleotide strands. These experiments revealed that a two-step modification of the silica surface with amino silane and succinic anhydride prior to coupling of an amino-terminated capture DNA (c-DNA) strand is superior to coupling carboxylic acid-terminated c-DNA to aminated core/shell particles, yielding limits of detection (LOD) down to 5 pM for a hybridization assay, using labeled complementary single-stranded target DNA (t-DNA) 15mers. The potential of the use of the particles in multiplexed analysis was shown with the aid of dye-doped core particles carrying a respective SBA-15 shell. Characteristic genomic sequences of human papillomaviruses (HPV) were chosen as the t-DNA analytes here, since their high relevance as carcinogens and the high number of different pathogens is a relevant model case. The title particles showed a promising performance and allowed us to unequivocally detect the different high- and low-risk HPV types in a single experimental run. KW - Bead-based assay KW - Core-shell particles KW - Human papillomavirus KW - Mesoporous silica KW - Multiplexing PY - 2020 DO - https://doi.org/10.1021/acsami.0c17940 SN - 1944-8244 VL - 13 IS - 1 SP - 207 EP - 218 PB - American Chemical Society CY - Washington, DC AN - OPUS4-51955 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Development of a Lab-on-a-Chip for the Detection of Nerve Agents with a Handheld Device N2 - The development of a Lab-on-a-Chip (LoC) is presented, which can detect reactive phosphorous compounds in the gas phase in combination with an optochemical hand-held sensor. The LoC prototype contains three pairs of sensing materials containing fluorescent indicator dyes in various carrier materials. By measuring the fluorescence response to phosphoryl chloride, a surrogate compound, the detection of chemical warfare agents (CWAs) in gas phase becomes possible within seconds, introducing a novel approach to CWA detection. T2 - IEEE Sensors Conference CY - Vienna, Austria DA - 29.10.2023 KW - Chemical warfare agents KW - Lab-on-a-chip KW - Handheld sensors KW - Toxic industrial chemicals KW - Fluorescence PY - 2023 AN - OPUS4-58815 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rettig, W. A1 - Rurack, Knut A1 - Sczepan, M. ED - Valeur, B. ED - Brochon, J.-C. ED - O.S. Wolfbeis, T1 - From cyanines to styryl bases-photophysical properties, photochemical mechanisms, and cation sensing abilities of charged and neutral polymethinic dyes KW - Cyaninfarbstoffe KW - Styrylfarbstoffe KW - Photophysik KW - Photochemie KW - Kationen KW - Sensor PY - 2001 SN - 3-540-67779-8 SN - 1617-1306 N1 - Serientitel: Springer Series on Fluorescence – Series title: Springer Series on Fluorescence VL - 1 SP - 125 EP - 155 PB - Springer CY - Berlin AN - OPUS4-2086 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Multifunctional hybrid microparticles for rapid cytometric and microfluidic mix-&-detect bioassays N2 - Besides the application-oriented parameters selectivity and sensitivity, simplicity and speed as well as robustness and reliability are the key features that determine success, dissemination and acceptance of analytical assays and methods for use in the field. For bioassays based on antibodies or nucleic acid binders, bead-based assays have become one of the main working horses of lab-based methods. However, these approaches are often limited by complicated and time-consuming workflows, which are mainly compensated by massive parallelisation, keeping the average cost and time-to-result within acceptable limits due to the sheer number and constant flow of samples processed. In on-site applications, where analyses need to be performed on suspicion or on demand because results are needed as quickly as possible for proactive decision making, the number, frequency and type of samples are much more diverse, so analytical assays need to be adapted to remain cost-effective and operable by non-expert users in environments where no lab infrastructure is available. With this in mind, we have developed a multifunctional hybrid microparticle platform that enables fast and simple mix-&-detect bioassays in combination with fluidic cytometry- and chip-based analytical methods. The present contribution will give an overview of the beads, their functions and how they can be combined with immunoanalytical and nucleic acid-based detection technologies. Starting from simple polymeric core/silica shell particles [1], we have progressively introduced coding [2,3], anti-fouling [2], high-surface area [4] and magnetic schemes [5] and in recent years have shown how these beads can be used in simple mix-&-detect assays for a range of different environmental, health and food analytes [1-5]. In addition to cytometry, we have also successfully implemented such assays using miniaturised microfluidic and strip-based approaches [6]. T2 - ANAKON 2025 CY - Leipzig, Germany DA - 10.03.2025 KW - Bead-based assay KW - Core-shell particles KW - Lab-on-a-chip KW - Mycotoxin PY - 2025 AN - OPUS4-62766 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Maus, M. T1 - Monitoring pH and solvent proticity with donor-acceptor-substituted biphenyls: a new approach towards highly sensitive and powerful fluorescent probes by tuning the molecular structure N2 - The ability and structural requirements of 4-dimethylamino-4-cyano-substituted biphenyls showing photoinduced intramolecular charge transfer (CT) to serve as hydrogen bond- or pH-sensitive fluorescent probes is investigated. The donor–acceptor (D–A) biphenyls I and II being planar in the CT excited state are most suitable as pH-sensitive fluorescent probes. The two compounds show analytically valuable features such as well-separated absorption and emission bands and signal changes spanning four orders of magnitude and can be employed in ratiometric, self-calibrating, and highly sensitive pH fluorosensing in the range 03.0.CO;2-3 SN - 1434-1948 SN - 1099-0682 VL - 2000 IS - 10 SP - 2271 EP - 2282 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-968 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut A1 - Al-Soufi, W. ED - Braslavsky, S. T1 - pH-Dependent Photophysics of 2,2'-Bipyridiyl-3-OL T2 - Workshop on Theoretical Organic (Photo) Chemistry ; 18th IUPAC Symposium on Photochemistry CY - Dresden, Germany DA - 2000-07-22 KW - pH KW - Photophysik KW - Bipyridyl OL PY - 2001 SN - 1010-6030 VL - 144 IS - 2-3 SP - 1 PB - Elsevier CY - Amsterdam AN - OPUS4-859 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mayer-Enthart, Elke A1 - Sialelli, Julien A1 - Rurack, Knut A1 - Resch-Genger, Ute A1 - Köster, D. A1 - Seitz, H. T1 - Toward Improved Biochips Based on Rolling Circle Amplification - Influences of the Microenvironment on the Fluorescence Properties of Labeled DNA Oligonucleotides KW - Rolling circle amplification KW - Fluorescence KW - Biochips KW - Microarrays KW - Signal amplification KW - Cy3-labeled oligonucleotides KW - DNA technology PY - 2008 DO - https://doi.org/10.1196/annals.1430.022 SN - 0077-8923 SN - 1749-6632 SN - 0094-8500 VL - 1130 SP - 287 EP - 292 PB - New York Academy of Sciences CY - New York, NY AN - OPUS4-17633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Schulz, Burkhard A1 - Reck, Günter A1 - Resch-Genger, Ute A1 - Bricks, J. A1 - Maus, M. T1 - Substituted 1,5-Diphenyl-3-benzothiazol-2-yl-Delta2-pyrazolines - Synthesis, X-ray Structure, Photophysics, and Cation Complexation Properties N2 - The spectroscopic properties of 1-phenyl-3-benzothiazol-2-yl-5-(4-R-phenyl)-2-pyrazolines are strongly dependent on both the electronic nature of the substituent R and solvent polarity. As revealed by spectroscopic studies as a function of solvent polarity as well as temperature, for electron-rich amino donor substituents in polar solvents, deactivation of the strongly emissive charge transfer (CT) state of the basic 1-phenyl-3-benzothiazol-2-yl-2-pyrazoline chromophore has to compete with a fast intramolecular electron transfer (ET) quenching reaction. In the case of the dimethylamino derivative (R = DMA), the rate constant of ET in acetonitrile was determined to ket = 3 × 1010 s-1. This ET process can be utilized for metal ion sensing by introducing nitrogen containing aza crown ether receptor units to the 4-position of the 5-phenyl group. The spectroscopically determined ET rates of the 5-(N-alkyl)anilino substituents, a DMA, a tetrathia- (AT415C5), and a tetraoxa-monoaza-15-crown-5 (A15C5) group, correlate with electrochemical data and increase in the order AT415C5 < A15C5 < DMA. The metal ion sensing abilities of the two crowned derivatives are presented, and the different signaling mechanisms include binding to the crown ether in the 4-R-position, chelate formation in the 3-benzothiazol-2-yl-2-pyrazoline moiety, and electrophotochemical detection. Furthermore, the rigid "pseudo spiro" geometry of the molecules, which holds the three substituents of the central 2-pyrazoline ring in a fixed prearrangement, was confirmed by X-ray structure analysis. KW - Farbstoff KW - Fluoreszenz KW - Kationen KW - Photophysik PY - 2000 DO - https://doi.org/10.1021/jp993404q SN - 1089-5639 SN - 1520-5215 VL - 104 IS - 26 SP - 6171 EP - 6188 PB - Soc. CY - Washington, DC AN - OPUS4-841 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Bricks, J.L. A1 - Slominskii, J.L. A1 - Resch-Genger, Ute T1 - Cation complexing fluorescence probes containing the benz[c,d]indole fluorophore PY - 1998 SN - 0143-7208 SN - 1873-3743 VL - 36 IS - 2 SP - 121 EP - 138 PB - Elsevier Science CY - Kidlington AN - OPUS4-2098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut A1 - Unger, Brita A1 - Müller, Ralf A1 - Resch-Genger, Ute T1 - SiO2-Gele als Matrices für Fluoreszenzmarker T2 - 75. Glastechnische Tagung CY - Wernigerode, Deutschland DA - 2001-05-21 PY - 2001 SP - 8 EP - 11 PB - DGG, Deutsche Glastechnische Gesellschaft e.V. CY - Frankfurt/M. AN - OPUS4-2084 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Resch-Genger, Ute A1 - Rurack, Knut T1 - Determination of the photoluminescence quantum yield of dilute dye solutions (IUPAC technical report) N2 - Procedures for the determination of photoluminescence quantum yields with optical methods are addressed, and challenges associated with these measurements are discussed. Special emphasis is dedicated to relative measurements of fluorescent (i.e., short excited-state lifetime), transparent, dilute dye solutions in conventional cuvettes in a 0°/90° measurement geometry. Recommendations on the selection of suitable quantum yield standards are presented, and requirements for the documentation of photoluminescence quantum yields are derived. KW - Absorption KW - Dilute dye solutions KW - Fluorescence KW - IUPAC Analytical Chemistry Division KW - IUPAC Organic and Biomolecular Chemistry Division KW - IUPAC Physical and Biophysical chemistry division KW - Luminescence KW - Photoluminescence quantum yields PY - 2013 DO - https://doi.org/10.1351/PAC-REP-12-03-03 SN - 0033-4545 SN - 1365-3075 VL - 85 IS - 10 SP - 2005 EP - 2026 PB - Union CY - Research Triangle Park, NC AN - OPUS4-29323 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Rurack, Knut A1 - Resch-Genger, Ute T1 - Design, Synthese und Charakterisierung von Fluoreszenzstandards und Fluoreszenzmarkern für die zeitaufgelöste Fluorometrie N2 - Im Rahmen dieses Projekts wurden Fluoreszenzfarbstoffe und neue intrinsische und konjugierte Fluoreszenzmarker mit Sauerstoff, Schwefel, Stickstoff-Heteromakrozyklen als kationenspezifische Rezeptoren für analytische Applikationen der zeitaufgelösten Fluorometrie von der Kiewer Gruppe synthetisiert. Die in Berlin an diesen Verbindungen durchgeführten fluorometrischen Charakterisierungen und spektroskopischen Untersuchungen zum Kationenkomplexierungsverfahren ermöglichten die Aufstellung von ersten Designprinzipien für Fluoreszenzmarker für Übergangs- und Schwermetallionen. T3 - BAM Forschungsberichtreihe - 223 PY - 1998 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-2273 SN - 978-3-89701-038-0 SN - 0938-5533 VL - 223 SP - 1 EP - 40 PB - Wirtschaftsverlag NW CY - Bremerhaven AN - OPUS4-227 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Resch-Genger, Ute A1 - Rurack, Knut ED - Lieberman, R. T1 - Steady-state and time-resolved fluorometry of fluorescent pollutants and heavy metal complexes N2 - Time-resolved laser-induced fluorescence spectroscopy is one of the most sensitive optical methods which is well suited for on-line in situ analysis. Here, three examples for the steady- state and time-resolved fluorescence analysis of environmentally important analytes, the fluorescent monoaromatic hydrocarbons benzene, toluene, and xylene as well as non fluorescent heavy metal ions forming a fluorescent complex with a cation coordinating fluorescence probe, are presented and the potential of both methods is discussed. For BTX, various mixtures of the spectrally similar compounds B, T, and X showing different fluorescence lifetimes were studied with both methods. As an example for fluorometric metal ion analysis, the fluorescence probe BP(OH)2 (2,2'-bipyridyl- 3,3'-diol) was employed for the determination of d10 metal ions in water and the newly developed fluorescence probe APTA for the detection of Cu(II). Cation complexation of BP(OH2 yields spectrally very similar complexes which differ in their fluorescence lifetimes. Complexation of APTA to Cu(II) leads to small spectral changes and a strong increase in fluorescence quantum yield and lifetime. For the analytes studied, a comparison of the detection limits, standard deviations, and linear dynamic range of both methods clearly demonstrates the analytical potential of time-resolved fluorometry. T2 - Conference CY - Munich, Germany DA - 1997-06-16 KW - Fluorescence KW - Time-resolved KW - Probe KW - Heavy metal ion KW - Cation complex PY - 1997 SN - 0-8194-2526-5 DO - https://doi.org/10.1117/12.276139 SN - 1605-7422 N1 - Serientitel: SPIE proceedings series – Series title: SPIE proceedings series IS - 3105 SP - 96 EP - 103 PB - SPIE CY - Bellingham, Wash. AN - OPUS4-2099 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Unger, Brita A1 - Rurack, Knut A1 - Müller, Ralf A1 - Jancke, Harald A1 - Resch-Genger, Ute T1 - Microscopic vs. macroscopic structural evolution of SiO2 sols and gels employing a tailor-made fluorescent reporter dye N2 - The short- and long-term structural evolution and aging of sol–gel materials prepared under mild conditions are studied by fluorometry, dynamic light scattering (DLS), 29Si NMR and gravimetry. In combination with the first, a newly developed donor–acceptor-substituted fluorescent probe with two acidophilic sites of different strength and topology is introduced. Its performance in detecting changes in parameters such as polarity, proticity, and pore volume on the microscopic scale is compared to two other dyes and to the macroscopic changes revealed by DLS, NMR and gravimetry. At early stages of the sol–gel process, fluorometry, DLS and NMR reveal similar changes which are typical of the structural evolution of SiO2 sols having different synthesis parameters. During later times of sol aging, DLS and NMR reflect the growth of the network and indicate that all sols approach similar structural equilibria. Fluorometry supports these findings by signalling a gradual decrease in mobile species with high proton activity. The formation of the spanning cluster upon gelation is strongly evident only from DLS results while the local environment of the fluorophore remains largely unchanged. However, the fluorescent dye is able to report microscopic changes even during long-term aging. Drying of the gels with a pronounced contraction of solvated pores is readily observable by fluorometry and gravimetry. During the late reaction stages, the fluorescence properties of the tailor-made dye are still sensitive toward the environment. PY - 2005 DO - https://doi.org/10.1039/b501622c SN - 0959-9428 SN - 1364-5501 VL - 15 IS - 30 SP - 3069 EP - 3083 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-10378 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 - JOUR A1 - Climent Terol, Estela A1 - Hecht, Mandy A1 - Witthuhn, Heike A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Mix‐&‐read determination of Mercury(II) at trace levels with hybrid mesoporous silica materials incorporating fluorescent probes by a simple mix‐&‐load technique N2 - The synthesis, characterization, and application of mesoporous materials containing boron–dipyrromethene (BODIPY) moieties that allow the sensitive and selective detection of HgII in aqueous environments by fluorescence enhancement is reported. For this purpose, BODIPY dye I containing a thia‐aza crown ether receptor as the fluorescent probe for the detection of HgII in aqueous environments is encapsulated into mesoporous materials to avoid self‐quenching or aggregation in water. Determination of HgII is accomplished within a few seconds with high selectivity and sensitivity, reaching a limit of detection of 12 ppt. The determination of trace amounts of HgII in natural waters and in fish extracts is demonstrated by using our sensing material. The incorporation of the material into several μ‐PAD strips yields a portable, cheap, quick, and easy‐to‐handle tool for trace HgII analysis in water. KW - Dyes/pigments KW - Test strips KW - Mesoporous materials KW - Mercury KW - Fluorescence PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-460138 DO - https://doi.org/10.1002/open.201800277 SN - 2191-1363 VL - 7 IS - 12 SP - 957 EP - 968 PB - Wiley-VCH CY - Weinheim AN - OPUS4-46013 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Alnajjar, M. A. A1 - Bartelmeß, Jürgen A1 - Hein, R. A1 - Ashokkumar, Pichandi A1 - Nilam, M. A1 - Nau, W. M. A1 - Rurack, Knut A1 - Hennig, A. T1 - Rational design of boron-dipyrromethene (BODIPY) reporter dyes for cucurbit[7]uril N2 - We introduce herein boron-dipyrromethene (BODIPY) dyes as a new class of fluorophores for the design of reporter dyes for supramolecular host–guest complex formation with cucurbit[7]uril (CB7). The BODIPYs contain a protonatable aniline nitrogen in the meso-position of the BODIPY chromophore, which was functionalized with known binding motifs for CB7. The unprotonated dyes show low fluorescence due to photoinduced electron transfer (PET), whereas the protonated dyes are highly fluorescent. Encapsulation of the binding motif inside CB7 positions the aniline nitrogen at the carbonyl rim of CB7, which affects the pKa value, and leads to a host-induced protonation and thus to a fluorescence increase. The possibility to tune binding affinities and pKa values is demonstrated and it is shown that, in combination with the beneficial photophysical properties of BODIPYs, several new applications of host–dye reporter pairs can be implemented. This includes indicator displacement assays with favourable absorption and emission wavelengths in the visible spectral region, fluorescence correlation spectroscopy, and noncovalent surface functionalization with fluorophores. KW - BODIPY KW - Cucurbituril KW - Fluorescence KW - PH KW - Photoinduced Electron Transfer KW - Supramolecular Chemistry PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-456361 UR - https://www.beilstein-journals.org/bjoc/content/pdf/1860-5397-14-171.pdf DO - https://doi.org/10.3762/bjoc.14.171 SN - 1860-5397 VL - 14 SP - 1961 EP - 1971 PB - Beilstein-Institut CY - Frankfurt a. M. AN - OPUS4-45636 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gotor, Raul A1 - Ashokkumar, Pichandi A1 - Hecht, Mandy A1 - Keil, Karin A1 - Rurack, Knut T1 - Optical pH Sensor Covering the Range from pH 0−14 Compatible with Mobile-Device Readout and Based on a Set of Rationally Designed Indicator Dyes N2 - In this work, a family of pH-responsive fluorescent probes has been designed in a rational manner with the aid of quantum chemistry tools, covering the entire pH range from 0−14. Relying on the boron−dipyrromethene (BODIPY) core, all the probes as well as selected reference dyes display very similar spectroscopic properties with ON−OFF fluorescence switching responses, facilitating optical readout in simple devices used for detection and analysis. Embedding of the probes and reference dyes into hydrogel spots on a plastic strip yielded a test strip that reversibly indicates pH with a considerably small uncertainty of ~0.1 pH units. These strips are not only reusable but, combined with a 3D-printed case that can be attached to a smartphone, the USB port of which drives the integrated LED used for excitation, allows for autonomous operation in on-site or in-the-field applications; the developed Android application software (“app”) further simplifies operation for unskilled users. KW - Fluorescence KW - pH measurement KW - BODIPY KW - Smartphone KW - Test strip PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-422571 DO - https://doi.org/10.1021/acs.analchem.7b01903 SN - 0003-2700 SN - 1520-6882 VL - 89 IS - 16 SP - 8437 EP - 8444 PB - American Chemical Society CY - Washington, D.C., USA AN - OPUS4-42257 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 - JOUR A1 - Bell, Jérémy A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Mit Tröpfchen Spielen N2 - Mikrofluidische Systeme sind leistungsstarke analytische Tools mit attraktiven Eigenschaften wie miniaturisierter Größe, geringem Reagenzien und Probenverbrauch, schneller Ansprech- und kurzer Messzeit. Der Bedarf solcher leistungsstarken, miniaturisierten und direkt vor Ort anwendbaren Sensorsysteme steigt kontinuierlich, hauptsächlich durch das Bedürfnis der Gesellschaft, schneller, besser und umfassender über kritische Faktoren im Lebens- und Arbeitsumfeld sowie der Umwelt informiert zu sein. KW - Mikrofluidik KW - Sensorpartikel PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-459120 UR - https://www.git-labor.de/forschung/umwelt/mit-troepfchen-spielen VL - 8 IS - 8 SP - 2 EP - 4 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim, Deutschland AN - OPUS4-45912 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bell, Jérémy A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Playing with Droplets N2 - Microfluidic devices are powerful analytical tools with appealing features such as miniaturized size, low reagent and sample consumption, rapid response and short measurement times. As society wants to be ever better, earlier and more comprehensively informed about critical factors in life, work, and the environment, the demand for powerful measurement devices for use outside of the laboratory constantly increases. KW - Microfluidics KW - Sensory particles PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-459131 UR - https://www.laboratory-journal.com/ VL - 4 SP - 2 EP - 4 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim, Deutschland AN - OPUS4-45913 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Climent Terol, Estela A1 - Hecht, Mandy A1 - Witthuhn, Heike A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Cover profile for the article "Mix‐&‐read determination of Mercury(II) at trace levels with hybrid mesoporous silica materials incorporating fluorescent probes by a simple mix‐&‐load technique" N2 - Invited for this month’s cover picture is the group of Dr. Knut Rurack at the Department of Analytical Chemistry; Reference Materials at the Bundesanstalt fuer Materialforschung und -pruefung (BAM) in Berlin (Germany). The cover picture shows how differences in color and fluorescence on a test strip can be easily read out with a mobile device. Two reference spots Frame the sensitive spot that indicates the presence of trace amounts of HgII below the threshold in a natural water sample. This dipstick contains a hybrid material that combines boron-dipyrromethene (BODIPY) probes sterically loaded into specifically tailored mesoporous silica particles, allowing for ultrasensitive HgII detection through enhanced fluorescence in a few seconds. The applicability in real water samples and fish extracts are also studied. KW - Mercury KW - Fluorescence KW - Dip-stick assay KW - Group profile PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471267 DO - https://doi.org/10.1002/open.201800231 SN - 2191-1363 VL - 7 IS - 12 SP - 932 EP - 933 PB - Wiley-VCH CY - Weinheim AN - OPUS4-47126 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 - 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 - JOUR A1 - Wan, Wei A1 - Wagner, Sabine A1 - Rurack, Knut T1 - Fluorescent monomers: "bricks" that make a molecularly imprinted polymer "bright" N2 - Molecularly imprinted polymers (MIPs) are potent and established recognition phases in separation and enrichment applications. Because of their robustness, versatility and format adaptability, they also constitute very promising sensing phases, especially when the active sensing element is directly integrated into the MIP. Fluorescent MIPs incorporating fluorescent monomers are perhaps the best developed and most successful approach here. This article reviews the state of the art in this field, discussing the pros and cons of the use of fluorescent dye and probe derivatives as such monomers, the different molecular interaction forces for template complexation, signalling modes and a variety of related approaches that have been realized over the years, including Förster resonance energy transfer processes, covalent imprinting, postmodification attachment of fluorescent units and conjugated polymers as MIPs; other measurement schemes and sensing chemistries that use MIPs and fluorescence interrogation to solve analytical problems (fluorescent competitive assays, fluorescent analytes, etc.) are not covered here. Throughout the article, photophysical processes are discussed to facilitate understanding of the effects that can occur when one is planning for a fluorescence response to happen in a constrained polymer matrix. The article concludes with a concise assessment of the suitability of the different formats for sensor realization. KW - Chemical sensors KW - Fluorescence KW - Molecularly imprinted polymers KW - Dyes KW - Sol-gel PY - 2016 DO - https://doi.org/10.1007/s00216-015-9174-4 SN - 1618-2642 SN - 1618-2650 VL - 408 IS - 7 SP - 1753 EP - 1771 PB - Springer CY - Berlin AN - OPUS4-35830 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bartelmeß, Jürgen A1 - Gawlitza, Kornelia A1 - Bartholmai, Matthias A1 - Rurack, Knut T1 - Developments towards the fluorescence based sensing of hazardous gases N2 - Fluorescence based sensing is a versatile approach for the trace analysis outside of the laboratory, requiring suitable sensor materials and their integration into sensing devices. The versatility of fluorophores as probes, especially in terms of the possibility to tailor their optical as well as their recognition properties by synthetic modifications in a wide range, renders them a superior active component for the preparation of optical sensor devices. Recent works at BAM in this field include, for example, the detection of nerve gas agents, illustrating impressively the aforementioned benefits of fluorophores in optical sensing applications. In the interdisciplinary approach presented here, we target hazardous gases such as ammonia, benzene, and hydrogen sulfide, next to others, which pose a major threat to human health and environmental safety and for which the availability of a sensitive and reliable detection method is highly desirable. The dyes presented follow a “turn-on” fluorescence schematic which allows for the selective and sensitive detection of the respective gaseous analyte. The immobilization of the probe in polymeric matrices is then the next step toward the fabrication of a prototype device for molecular sensing. T2 - Colloquium of Optical Spectrometry (COSP) 2017 CY - Berlin, Germany DA - 27.11.2017 KW - Gas sensing KW - Fluorescence KW - KonSens PY - 2017 AN - OPUS4-43209 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 - Climent Terol, Estela A1 - Biyikal, Mustafa A1 - Gawlitza, Kornelia A1 - Dropa, T. A1 - Urban, M. A1 - Costero, A. M. A1 - Martínez-Mánez, Ramon A1 - Rurack, Knut T1 - A rapid and sensitive strip-based quick test for nerve agents Tabun, Sarin, and Soman using BODIPY-modified silica materials N2 - Test strips that in combination with a portable fluorescence reader or digital camera can rapidly and selectively detect chemical warfare agents (CWAs) such as Tabun (GA), Sarin (GB), and Soman (GD) and their simulants in the gas phase have been developed. The strips contain spots of a hybrid indicator material consisting of a fluorescent BODIPY indicator covalently anchored into the channels of mesoporous SBA silica microparticles. The fluorescence quenching response allows the sensitive detection of CWAs in the μg m−3 range in a few seconds. KW - Chemical warfare agents KW - Fluorescence KW - Hybrid sensor materials KW - Nerve gases KW - Test strip analysis PY - 2016 DO - https://doi.org/10.1002/chem.201601269 SN - 0947-6539 SN - 1521-3765 VL - 22 IS - 32 SP - 11138 EP - 11142 PB - Wiley CY - Online Library AN - OPUS4-37063 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Fluorescent mesoporous silicia materials discriminating Ag(l) and Hg (II) T2 - 25th Congress of the Analytical Chemistry Division of the Italian Chemical Society CY - Trieste, Italien DA - 2015-09-13 PY - 2015 AN - OPUS4-33635 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gawlitza, Kornelia A1 - Fischer, Tobias A1 - Rurack, Knut T1 - Chemical functionalization for quantitative spectroscopic labeling on macroscopically flat surfaces N2 - This chapter highlights the application of chemical derivatization (CD) to facilitate the quantification of surface functional groups being an important issue for a wide field of applications. The selective attachment of a chemical label to a surface functional group being afterwards exclusively detectable by a highly sensitive technique overcomes the problem of characterizing low amounts of functional groups on macroscopically flat surfaces. The most frequently employed methods include CD X-ray photoelectron spectroscopy, ultraviolet/visible absorption, and fluorescence spectroscopy, as well as time-of-flight secondary ion mass spectrometry. Herein, the basic conditions for the different techniques regarding the specific surface functional group which need to be quantified are discussed. Additionally, the substrate highly influences the compatibility of the corresponding method. Because not just the quantification but also the preparation of the desired application is important, a summary of different preparation methods for glass, polymer and gold substrates is presented. KW - Chemical derivatization KW - Fluorescence KW - Surface group quantification KW - Time-of-flight secondary ion mass spectrometry KW - UV/vis spectroscopy KW - X-ray photoelectron spectroscopy PY - 2018 SN - 978-0-12-409547-2 DO - https://doi.org/10.1016/B978-0-12-409547-2.13191-9 SP - 1 PB - Elsevier AN - OPUS4-43767 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 - Rurack, Knut T1 - Combining Fluorescent Probes, Functionalized Surfaces, Tailored Particles and Device Embedding for Robust, Reliable and User-friendly Analytical Assays N2 - Supramolecular chemistry, fluorescence detection, hybrid (nano)materials and device miniaturization are in themselves highly interesting areas of research, yet especially their combination paves the way to (bio)chemical analysis systems that show outstanding performance. The lecture gives an overview of the toolbox of single components developed in BAM’s Chemical and Optical Sensing Division over the years, and how their combination can result in powerful sensors, quick tests and assays. While at the core of a development is the analytical problem, that is, the determination of a certain analyte in a sample of interest with the required sensitivity and selectivity by a specific end user in a given setting, signaling mechanisms, recognition elements, signal transduction modes, materials functionalization, device design and system integration are adequately chosen, tailored and adapted. Examples including molecularly imprinted polymers, hybrid mesoporous nanomaterials, gated indicator release systems, microfluidic devices, test strips and smartphone-based analysis will be presented. T2 - GDCh CY - Chemnitz, Germany DA - 21.06.2018 KW - Fluorescence KW - Particles KW - Rapid tests KW - Device embedding PY - 2018 AN - OPUS4-45640 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Molecularly Imprinted Polymers with Integrated Fluorescence as Versatile Biomimetic Sensing Matrices N2 - Molecularly imprinted polymers (MIPs) are an established, versatile and high-performance matrix for the selective separation or enrichment of (bio)chemical species, especially small molecules of biochemical or environmental relevance. MIPs are prepared through the polymerization of a mixture of functional monomers and cross-linkers in the presence of the template with subsequent extraction of the latter. Conceptionally, this process can be seen as mimicking in a strongly accelerated, though single-step manner a biological process such as antibody formation. Because the resulting MIPs contain cavities in their matrix that are complementary in size, shape and electronic/ electrostatic or hydrogen bonding demand to the imprinted target molecule or template, these polymers are frequently termed “artificial antibodies”. Compared to natural antibodies, they are chemically and physically much more robust. Regarding sensitivity and selectivity, however, there is still a gap to bridge before MIPs can fully compete with antibodies. Another favorable aspect that distinguishes MIPs from antibodies is that they can be endowed with an explicit function, allowing the use of MIPs in applications that require more than only an efficient binder. For instance, if specifically designed and polymerizable fluorescent indicators are integrated as functional monomers into a MIP, direct fluorescence sensing can be accomplished. Because MIPs can be prepared in a variety of different formats, their combination with miniaturized or other specific analytical techniques or sensory devices is possible, especially when the transduction mode is light. This presentation will introduce basic design considerations, challenges, limitations and the potential that lies with such sensor materials with some recent examples of our group, targeting various organic oxoanions as analytes. T2 - 8th International Symposium on Bioanalysis, Biomedical Engineering and Nanotechnology CY - Changsha, Hunan, China DA - 25.05.2018 KW - Molecularly imprinted polymers KW - Fluorescence KW - Anion recognition PY - 2018 AN - OPUS4-45641 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shinde, S. A1 - El-Schich, Z. A1 - Malakpour, A. A1 - Wan, Wei A1 - Dizeyi, N. A1 - Mohammadi, R. A1 - Rurack, Knut A1 - Gjörloff Wingren, A. A1 - Sellergren, B. T1 - Sialic acid-imprinted fluorescent core-shell particles for selective labeling of cell surface glycans N2 - The expression of cell surface glycans terminating with sialic acid (SA) residues has been found to correlate with various disease states there among cancer. We here report a novel strategy for specific fluorescence labeling of such motifs. This is based on sialic acid-imprinted core–shell nanoparticles equipped with nitrobenzoxadiazole (NBD) fluorescent reporter groups allowing environmentally sensitive fluorescence detection at convenient excitation and emission wavelengths. Imprinting was achieved exploiting a hybrid approach combining reversible boronate ester formation between p-vinylphenylboronic acid and SA, the introduction of cationic amine functionalities, and the use of an NBD-appended urea-monomer as a binary hydrogen-bond donor targeting the SA carboxylic acid and OH functionalities. The monomers were grafted from 200 nm RAFT-modified silica core particles using ethylene glycol dimethacrylate (EGDMA) as cross-linker resulting in a shell thickness of ca. 10 nm. The particles displayed strong affinity for SA in methanol/water mixtures (K = 6.6 × 105 M-1 in 2% water, 5.9 × 103 M-1 in 98% water, Bmax ≈ 10 µmol g-1), whereas binding of the competitor glucuronic acid (GA) and other monosaccharides was considerably weaker (K (GA) = 1.8 × 103 M-1 in 98% water). In cell imaging experiments, the particles selectively stained different cell lines in correlation with the SA expression level. This was further verified by enzymatic cleavage of SA and by staining using a FITC labeled SA selective lectin. KW - Glycoproteine KW - Biomarker KW - Fluoreszenz KW - Polymere KW - Krebsdiagnostik PY - 2015 DO - https://doi.org/10.1021/jacs.5b08482 SN - 0002-7863 SN - 1520-5126 VL - 137 IS - 43 SP - 13908 EP - 13912 PB - American Chemical Society CY - Washington, DC, USA AN - OPUS4-35227 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 - JOUR A1 - Muguruza, A.R. A1 - Odyniec, M.L. A1 - Manhota, M. A1 - Habib, Z. A1 - Rurack, Knut A1 - Blair, J.M.A. A1 - Kuehne, S.A. A1 - Walmsley, A.D. A1 - Pikramenou, Z. T1 - Antibiotic entrapment in antibacterial micelles as a novel strategy for the delivery of challenging antibiotics from silica nanoparticles N2 - Silica materials are popular in biomedical applications as composites and drug delivery platforms due to their low toxicity and biocompatibility. Mesoporous silica nanoparticles are attractive drug delivery systems based on their porous silica framework with high surface area. In the preparation of mesoporous silica frameworks, most commonly, MCM-41, the efficient removal of the template responsible for introducing porous networks, cetyltrimethyl ammonium bromide (CTAB), is a critical step due to the template’s high toxicity in the environment and human health. In this work, we present a new one-pot approach of introducing challenging antibiotics within a silica framework without the need of toxic templates, but instead using micelle formation by an antibacterial agent. We demonstrate that micelles formed by cetylpyridinium chloride (CPC), a known antibacterial agent, entrap antibiotics such as rifampicin and ciprofloxacin. Extensive NMR studies elucidate the precise localisation of the antibiotic within the CPC micelle. Ciprofloxacin is placed between the outer and palisade region while rifampicin is located further into the hydrophobic CPC micelle core. In both cases, the formation of the silica framework can be built around the CPC-antibiotic loaded micelles. The resulting silica nanoparticles show loading of both CPC and antibiotic agents, porosity and dual antibacterial release upon disruption of the micelle within the silica framework. The design not only provides a strategy of a therapeutic design to form porous frameworks but also highlights the potential of precise antibiotic dose and release in nanoparticle systems. KW - Silica KW - Nanoparticles KW - Antibiotics KW - Drug delivery KW - Surfactants PY - 2024 DO - https://doi.org/10.1016/j.micromeso.2023.112841 SN - 1387-1811 VL - 363 SP - 1 EP - 11 PB - Elsevier Inc. CY - Amsterdam AN - OPUS4-58534 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fischer, Tobias A1 - Dietrich, Paul A1 - Unger, Wolfgang A1 - Rurack, Knut T1 - Multimode surface functional group determination: combining steady-state and time-resolved fluorescence with X‑ray photoelectron spectroscopy and absorption measurements for absolute quantification N2 - The quantitative determination of surface functional groups is approached in a straightforward laboratory-based method with high reliability. The application of a multimode BODIPY-type fluorescence, photometry, and X-ray photoelectron spectroscopy (XPS) label allows estimation of the labeling ratio, i.e., the ratio of functional groups carrying a label after reaction, from the elemental ratios of nitrogen and fluorine. The amount of label on the surface is quantified with UV/vis spectrophotometry based on the molar absorption coefficient as molecular property. The investigated surfaces with varying density are prepared by codeposition of 3-(aminopropyl) triethoxysilane (APTES) and cyanoethyltriethoxysilane (CETES) from vapor. These surfaces show high functional group densities that result in significant fluorescence quenching of surface-bound labels. Since alternative quantification of the label on the surface is available through XPS and photometry, a novel method to quantitatively account for fluorescence quenching based on fluorescence lifetime (τ) measurements is shown. Due to the complex distribution of τ on high-density surfaces, the stretched exponential (or Kohlrausch) function is required to determine representative mean lifetimes. The approach is extended to a commercial Rhodamine B isothiocyanate (RITC) label, clearly revealing the problems that arise from such charged labels used in conjunction with silane surfaces. KW - surface group quantification KW - fluorescence spectroscopy KW - absorption spectroscopy KW - X-ray photoelectron spectroscopy KW - dyes PY - 2016 DO - https://doi.org/DOI: 10.1021/acs.analchem.5b03468 SN - 0003-2700 VL - 88 IS - 2 SP - 1210 EP - 1217 PB - American Chemical Society CY - Washington, DC AN - OPUS4-35832 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ast, S. A1 - Fischer, Tobias A1 - Müller, H. A1 - Mickler, W. A1 - Schwichtenberg, M. A1 - Rurack, Knut A1 - Holdt, H.-J. T1 - Integration of the 1,2,3-triazole 'click' motif as a potent signalling element in metal ion responsive fluorescent probes N2 - In a systematic approach we synthesized a new series of fluorescent probes incorporating donor–acceptor (D-A) substituted 1,2,3-triazoles as conjugative π-linkers between the alkali metal ion receptor N-phenylaza-[18]crown-6 and different fluorophoric groups with different electron-acceptor properties (4-naphthalimide, meso-phenyl-BODIPY and 9-anthracene) and investigated their performance in organic and aqueous environments (physiological conditions). In the charge-transfer (CT) type probes 1, 2 and 7, the fluorescence is almost completely quenched by intramolecular CT (ICT) processes involving charge-separated states. In the presence of Na+ and K+ ICT is interrupted, which resulted in a lighting-up of the fluorescence in acetonitrile. Among the investigated fluoroionophores, compound 7, which contains a 9-anthracenyl moiety as the electron-accepting fluorophore, is the only probe which retains light-up features in water and works as a highly K+/Na+-selective probe under simulated physiological conditions. Virtually decoupled BODIPY-based 6 and photoinduced electron transfer (PET) type probes 3–5, where the 10-substituted anthracen-9-yl fluorophores are connected to the 1,2,3-triazole through a methylene spacer, show strong ion-induced fluorescence enhancement in acetonitrile, but not under physiological conditions. Electrochemical studies and theoretical calculations were used to assess and support the underlying mechanisms for the new ICT and PET 1,2,3-triazole fluoroionophores. KW - Charge transfer KW - Click chemistry KW - Electron transfer KW - Fluorescent probes KW - Metal ions PY - 2013 DO - https://doi.org/10.1002/chem.201201575 SN - 0947-6539 SN - 1521-3765 VL - 19 IS - 9 SP - 2990 EP - 3005 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nöll, G. A1 - Daub, J. A1 - Lutz, M. A1 - Rurack, Knut T1 - Synthesis, spectroscopic properties, and electropolymerization of azulene dyads N2 - Four azulene dyads have been synthesized and studied by spectroscopic and electrochemical methods. A triarylamine, a boron-dipyrromethene (BDP or BODIPY), a porphyrin, and an isoalloxazine moiety have been linked to an extended π electron system at the 2-position of azulene, leading to the dyads 1–4, respectively. For the synthesis of 1–4, first 2-(4-ethynyl-phenyl)azulene (EPA) was prepared, which was further reacted with the halogenated chromophores by Pd-catalyzed cross-coupling reactions. The dyads 1–4 exhibit strong absorption bands in the visible range, which are dominated by the absorption spectra of the individual subchromophores. Fluorometric studies of 2–4 revealed that after excitation of the subchromophoric unit attached to the parent azulene moiety, quenching mainly through energy transfer to azulene is effective, whereas possible charge-transfer interactions play only a minor role. Potentiodynamic oxidation of the dyads 1–4 leads to the formation of polymer films, which are deposited at the electrode. The polymer film derived from 1 was further characterized by spectroelectrochemistry. During positive doping of poly-1, a strong absorption band appears at 13,200 cm–1, which is typical for triarylamine radical cations. This band is overlapping with a broad absorption band in the low-energy region that might be caused by charge-transfer interactions within the polymer. KW - Azulen KW - Elektropolymerisation KW - Energietransfer KW - Farbstoffe KW - Fluoreszenz PY - 2011 DO - https://doi.org/10.1021/jo200080v SN - 0022-3263 SN - 1520-6904 VL - 76 IS - 12 SP - 4859 EP - 4873 PB - American Chemical Society CY - Washington, DC AN - OPUS4-23987 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hecht, Mandy A1 - Fischer, Tobias A1 - Dietrich, Paul A1 - Kraus, Werner A1 - Descalzo López, Ana Belén A1 - Unger, Wolfgang A1 - Rurack, Knut T1 - Fluorinated Boron-Dipyrromethene (BODIPY) dyes: bright and versatile probes for surface analysis N2 - A family of bright boron-dipyrromethene-type fluorophores with a high number of fluorine atoms (F-BODIPYs) has been developed and characterized by X-ray crystallography and optical spectroscopy. The introduction of 3,5-bis(trifluoromethyl)phenyl and pentafluorophenyl moieties significantly enhances the photostability of such dyes, yielding for instance photostable near-infrared (NIR) fluorophores that show emission maxima>750 nm, when the BODIPY's π system is extended with two (dimethylamino)styryl and (dimethylamino)naphthastyryl moieties, or green-emitting BODIPYs with fluorescence quantum yields of unity. When equipped with a suitable group that selectively reacts for instance with amines, F-BODIPYs can be used as potent dual labels for the quantification of primary amino groups on surfaces by X-ray photoelectron spectroscopy (XPS) and fluorescence, two powerful yet complementary tools for the analysis of organic surface functional groups. The advantage of reactive F-BODIPYs is that they allow a fast and non-destructive mapping of the labelled supports with conventional fluorescence scanners and a subsequent quantification of selected areas of the same sample by the potentially traceable XPS technique. The performance is exemplarily shown here for the assessment of the amino group density on SiO2 supports, one of the most common reactive silica supports, in particular, for standard microarray applications. KW - Amino groups KW - Dyes KW - Fluorescence KW - Surface analysis KW - X-ray photoelectron spectroscopy KW - Amino-Gruppen KW - Farbstoffe KW - Fluoreszenz KW - Oberflächenanalytik KW - Röntgen-Photoelektronen-Spektroskopie PY - 2013 DO - https://doi.org/10.1002/open.201200039 SN - 2191-1363 VL - 2 IS - 1 SP - 25 EP - 38 PB - Wiley-VCH-Verl. CY - Weinheim AN - OPUS4-27783 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hecht, Mandy A1 - Kraus, Werner A1 - Rurack, Knut T1 - A highly fluorescent pH sensing membrane for the alkaline pH range incorporating a BODIPY dye N2 - A robust and re-usable dipstick-type fluorescent pH sensor for the alkaline pH range was developed by embedding a brightly fluorescent boron–dipyrromethene (BODIPY) dye bearing an acidic phenol moiety into a polyurethane matrix immobilized on a 3D epoxy-functionalized polymer support. The sensor strip has a dynamic working range of pH 10.0–13.1, i.e., operates in strongly basic media where pH glass electrodes can suffer from alkaline errors, and tolerates a high electrolyte background such as simulated seawater and sewage. This work describes the preparation of the sensing material and provides insight into the features that a hydrogel sensing membrane can bestow on an embedded pH-responsive dye by means of optical spectroscopic investigations. KW - pH-Wert KW - Farbstoffe KW - Fluoreszenz KW - Teststreifen KW - Hydrogel PY - 2013 DO - https://doi.org/10.1039/c2an35860c SN - 0003-2654 SN - 1364-5528 VL - 138 IS - 1 SP - 325 EP - 332 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-27638 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Biyikal, Mustafa A1 - Hecht, Mandy A1 - Martínez-Mánez, Ramon A1 - Rurack, Knut A1 - Sancenón, F. ED - Gale, P.A. ED - Steed, J.W. T1 - Supramolecular hybrid nanomaterials as prospective sensing platforms N2 - Supramolecular interactions are vital processes in many chemical sensors, biochemical assays, and other analytical detection schemes. On the background of the current, rapidly developing, and constantly changing requirements for (bio)analytical techniques, the classical molecular host is increasingly overburdened to accomplish a specific analytical task with the desired selectivity and sensitivity. Instead, other signaling strategies have to be conceived that overcome the limits in signal output, dynamic range, or compound targeting, which are imminent to various traditional methods. A very promising approach is the combination of concepts of supramolecular chemistry with nanostructured or nanoscopic inorganic materials, that is, the development of hybrid sensor materials. Such hybrids often lead to improved functionality and enhanced performance, and the present chapter discusses the contributory features in relation to the major aspects, which are related to the enhanced coordination by the preorganization of binding sites, signal amplification by the preorganization on surfaces, aggregation‐mediated signaling, surface‐modification‐based signaling, the tuning of selectivity through polarity and size, and gated signaling. KW - Supramolekulare Chemie KW - Optische Sonden KW - Nanotechnologie KW - Hybridmaterialien KW - Fluorescence KW - Hybrid nanomaterials KW - Optical sensors KW - Redox sensors KW - Supramolecular chemistry PY - 2012 SN - 978-0-470-74640-0 DO - https://doi.org/10.1002/9780470661345.smc199 SP - 3669 EP - 3698 PB - John Wiley & Sons AN - OPUS4-26118 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Biological and Biomimetic Approaches toward the Detection of Nitro- and Peroxide-based Explosives T2 - International Workshop on Explosives Detection 2010 CY - Valencia, Spain DA - 2010-11-25 PY - 2010 AN - OPUS4-22869 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Molecularly Imprinted Polymer Films as Sensory Materials for the Selective Detection of Carboxylates via Flourescence T2 - European Polymer Congress 2011(EPF) CY - Granada, Spain DA - 2011-06-26 PY - 2011 AN - OPUS4-23931 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Organically functionalized mesopporous silica particles as a versatile platform for Hg2+ determination, sequestration and CH3Hg+ speciation witz simple analytical protocols T2 - ANAKON 2011 CY - Zurich, Switzerland DA - 2011-03-22 PY - 2011 AN - OPUS4-23936 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Implementing Signal Amplification Features with Gated Mesoporous Sensory Hybrids for Methymercury Determination T2 - Hybrid Materials 2011 CY - Strasbourg, France DA - 2011-03-03 PY - 2011 AN - OPUS4-23935 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -