TY - JOUR A1 - Descalzo López, Ana Belén A1 - Marcos, M. Dolores A1 - Monte, Christian A1 - Martínez-Mánez, Ramon A1 - Rurack, Knut T1 - Mesoporous silica materials with covalently anchored phenoxazinone dyes as fluorescent hybrid materials for vapour sensing KW - Anorganisch-organische Hybridmaterialien KW - Sensorik KW - Fluoreszenz KW - Flüchtige organische Verbindungen PY - 2007 DO - https://doi.org/10.1039/b707473e SN - 0959-9428 SN - 1364-5501 VL - 17 SP - 4716 EP - 4723 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-16139 LA - eng 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 - 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 - 2008 SN - 978-0470-51644-7 SP - 31 EP - 50 PB - Wiley CY - Chichester AN - OPUS4-19213 LA - eng 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 - OPUS4-19133 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 -