TY - JOUR A1 - Sun, Yijuan A1 - Gawlitza, Kornelia A1 - Valderrey, Virginia A1 - Bhattacharya, Biswajit A1 - Rurack, Knut T1 - Ratiometric Molecularly Imprinted Particle Probes for Reliable Fluorescence Signaling of Carboxylate-Containing Molecules N2 - In addition to sensitivity, selectivity, and portability, chemical sensing systems must generate reliable signals and offer modular configurability to address various small molecule targets, particularly in environmental applications. We present a versatile, modular strategy utilizing ratiometric molecularly imprinted particle probes based on BODIPY indicators and dyes for recognition and internal referencing. Our approach employs polystyrene core particles doped with a red fluorescent BODIPY as an internal standard, providing built-in reference for environmental influences. A molecularly imprinted polymer (MIP) recognition shell, incorporating a green-fluorescent BODIPY indicator monomer with a thiourea binding site for carboxylate containing analytes, is grafted from the core particles in the presence of the analyte as the template. The dual-fluorescent MIP probe detects fexofenadine as the model analyte with a change in green emission signal referenced against a stable red signal, achieving a detection limit of 0.13 μM and a broad dynamic range from 0.16 μM to 1.2 mM, with good discrimination against other antibiotics in acetonitrile. By selecting a versatile dye scaffold and recognition element, this approach can be extended to other carboxylate-containing analytes and/or wavelength combinations, potentially serving as a robust multiplexing platform. KW - Core-shell particles KW - Molecular imprinting KW - Pharmaceutical contaminants KW - Self-referenced measurements KW - Fluorescence PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609385 DO - https://doi.org/10.1021/acsami.4c09990 SP - 1 EP - 13 PB - American Chemical Society (ACS) AN - OPUS4-60938 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tobias, Charlie A1 - López-Puertollano, Daniel A1 - Abad-Somovilla, Antonio A1 - Mercader, J. V. A1 - Abad-Fuentes, A. A1 - Rurack, Knut T1 - Development of Simple and Rapid Bead-Based Cytometric Immunoassays Using Superparamagnetic Hybrid Core−Shell Microparticles N2 - Flow cytometry-based immunoassays are valuable in biomedical research and clinical applications due to their high throughput and multianalyte capability, but their adoption in areas such as food safety and environmental monitoring is limited by long assay times and complex workflows. Rapid, simplified bead-based cytometric immunoassays are needed to make these methods viable for point-of-need applications, especially with the increasing accessibility of miniaturized cytometers. This work introduces superparamagnetic hybrid polystyrene-silica core−shell microparticles as promising alternatives to conventional polymer beads in competitive cytometric immunoassays. These beads, featuring high specificity, sensitivity, and excellent handling capabilities via magnetic separation, were evaluated with three different antibodies and binding methods, showing variations in signal intensity based on the antibody and its attachment method. The optimal performance was achieved through a secondary antibody binding approach, providing strong and consistent signals with minimal uncertainty. The optimized protocol made it possible to achieve a detection limit of 0.025 nM in a total assay time of only 15 min and was successfully used to detect ochratoxin A (OTA) in raw flour samples. This work highlights the potential of these beads as versatile tools for flow cytometry-based immunoassays, with significant implications for food safety, animal health, environmental monitoring, and clinical diagnostics. KW - Immunoassays KW - Bead-based KW - Core-shell particles KW - Cytometry KW - Mycotoxins PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610593 DO - https://doi.org/10.1021/acsmeasuresciau.4c00038 SP - 1 EP - 11 PB - American Chemical Society CY - Washington, D.C. AN - OPUS4-61059 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Descalzo López, Ana Belén A1 - Rurack, Knut A1 - Weißhoff, Hardy A1 - Martínez-Mánez, Ramon A1 - Marcos, M. Dolores A1 - Amorós, P. A1 - Hoffmann, Katrin A1 - Soto, J. T1 - Rational Design of a Chromo- and Fluorogenic Hybrid Chemosensor Material for the Detection of Long-Chain Carboxylates N2 - A strategy for the rational design of a new optical sensor material for the selective recognition of long-chain carboxylates in water is presented. The approach relies on the combination of structure-property relationships to single out the optimal molecular sensor unit and the tuning of the sensing characteristics of an inorganic support material. A spacer-substituted 7-urea-phenoxazin-3-one was employed as the signaling moiety and a mesoporous trimethylsilylated UVM-7 (MCM-41 type) material served as the solid support. The sensor material shows the advantageous features of both modules that is absorption and emission in the visible spectral range, a fluorescence red-shift and enhancement upon analyte coordination, and the amplification of noncovalent (binding) and hydrogen-bonding (recognition) interactions in the detection event. Besides these basic results that are related to the design and performance of the sensor material, the paper discusses general aspects of amido-substituted phenoxazinone photophysics and addresses some general features of molecular anion recognition chemistry in aqueous vs nonaqueous media, utilizing steady-state and time-resolved optical as well as NMR spectroscopies. Detailed studies on potentially competing biochemical species and a first access to the schematic model of the response of the sensor material as obtained by a combination of fluorescence lifetime distribution analysis and Langmuir-type fitting of the gross binding constants complement the key issues of the paper. KW - Chemosensor KW - Carboxylate KW - Rationales Design KW - Hybridmaterialien KW - Fluoreszenz PY - 2005 DO - https://doi.org/10.1021/ja045683n SN - 0002-7863 SN - 1520-5126 VL - 127 SP - 184 EP - 200 PB - American Chemical Society CY - Washington, DC AN - OPUS4-5985 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xu, H.-J. A1 - Mack, J. A1 - Wu, D. A1 - Xue, Z.-L. A1 - Descalzo López, Ana Belén A1 - Rurack, Knut A1 - Kobayashi, N. A1 - Shen, Z. T1 - Synthesis and properties of fused-ring-expanded porphyrins that were core-modified with group 16 heteroatoms N2 - The synthesis of a series of novel core-modified and fused-ring-expanded tetraphenylporphyrins is reported. Theoretical calculations and magnetic circular dichroism (MCD) and fluorescence spectroscopic measurements were used to analyze the effect of core modification with Group 16 oxygen, sulfur, selenium, and tellurium atoms on the optical properties and electronic structures of the porphyrins. Marked redshifts of the Q and B bands and accelerated intersystem-crossing rates were observed, thus making these compounds potentially suitable for use in a variety of applications. The scope for further fine-tuning of these optical properties based on additional structural modifications, such as the incorporation of fused benzene rings to form ABAB structures by using a thiophene precursor with a fused bicyclo[2.2.2]octadiene ring and the introduction of various substituents onto the meso-phenyl rings, is also examined. KW - Density functional calculations KW - Fluorescence KW - MCD spectroscopy KW - Porphyrinoids KW - Ring expansion PY - 2012 DO - https://doi.org/10.1002/chem.201200956 SN - 0947-6539 SN - 1521-3765 VL - 18 IS - 52 SP - 16844 EP - 16867 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27488 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mansurova, Maria A1 - Johann, Sergej A1 - Kohlhoff, Harald A1 - Rurack, Knut A1 - Bartholmai, Matthias A1 - Bell, Jérémy T1 - On-Site Analytical Tool Based on Crude Oil Fluorescence and Chemometrics for the Rapid Determination of the Nature and Essential Properties of Oil Spills N2 - With the reduction of large oil spills because of stricter regulations and safety measures, the question of how to manage smaller oil spills arises. Few on-site analytical tools are available for first responders or other law enforcement personnel to rapidly test for crude oil in the early management of localized polluted areas. The approach reported here relies on well-described computer-assisted multivariate data analysis of the intrinsic fluorescence fingerprints of crude oils to build a multivariate model for the rapid classification of crude oils and the prediction of their properties. Thanks to a dedicated robust portable reader, the method allowed classification and accurate prediction of various properties of crude oil samples like density (according to API, the American Petroleum Institute and viscosity as well as composition parameters such as volume fractions of paraffins or aromatics. In this way, autonomous operation in on-site or in-the-field applications becomes possible based on the direct (undiluted and untreated) measurement of samples and a rapid, tablet-operated readout system to yield a robust and simple analytical test with superior performance. Testing in real-life scenarios allowed the successful classification and prediction of a number of oil spill samples as well as weathered samples that closely resemble samples collected by first responders. KW - Oil spills KW - Fluorescence KW - PCA KW - Petroleum KW - Rapid test KW - Portable PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595442 DO - https://doi.org/10.1021/acsestwater.3c00648 VL - 4 IS - 2 SP - 621 EP - 627 PB - American Chemical Society (ACS) AN - OPUS4-59544 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kislenko, Evgeniia A1 - Incel, A. A1 - Gawlitza, Kornelia A1 - Sellergren, B. A1 - Rurack, Knut T1 - Towards molecularly imprinted polymers that respond to and capture phosphorylated tyrosine epitopes using fluorescent bis-urea and bis-imidazolium receptors N2 - Early detection of cancer is essential for successful treatment and improvement in patient prognosis. Deregulation of post-translational modifications (PTMs) of proteins, especially phosphorylation, is present in many types of cancer. Therefore, the development of materials for the rapid sensing of low abundant phosphorylated peptides in biological samples can be of great therapeutic value. In this work, we have synthesised fluorescent molecularly imprinted polymers (fMIPs) for the detection of the phosphorylated tyrosine epitope of ZAP70, a cancer biomarker. The polymers were grafted as nanometer-thin shells from functionalised submicron-sized silica particles using a reversible addition-fragmentation chain-transfer (RAFT) polymerisation. Employing the combination of fluorescent urea and intrinsically cationic bis-imidazolium receptor cross-linkers, we have developed fluorescent sensory particles, showing an imprinting factor (IF) of 5.0. The imprinted polymer can successfully distinguish between phosphorylated and non-phosphorylated tripeptides, reaching lower micromolar sensitivity in organic solvents and specifically capture unprotected peptide complements in a neutral buffer. Additionally, we have shown the importance of assessing the influence of counterions present in the MIP system on the imprinting process and final material performance. The potential drawbacks of using epitopes with protective groups, which can co-imprint with targeted functionality, are also discussed. KW - Functional monomers KW - Molecularly imprinted polymers KW - Phosphorylated peptides KW - Fluorescence KW - Core-shell particles PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588089 DO - https://doi.org/10.1039/d3tb01474f SN - 2050-750X SP - 1 EP - 10 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-58808 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Climent Terol, Estela A1 - Mondragón, L. A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Marcos, M. Dolores A1 - Murguía, J.R. A1 - Amorós, P. A1 - Rurack, Knut A1 - Pérez-Payá, E. T1 - Selective, highly sensitive, and rapid detection of genomic DNA by using gated materials: Mycoplasma detection N2 - Come and gate it: DNA-capped mesoporous silica nanoparticles loaded with a dye are used to detect the common contaminate Mycoplasma in real contaminated cell-culture media without needing polymerase chain reaction (PCR) techniques, at a detection limit in the range of 70 DNA genome copies µL-1. KW - DNA KW - Gated materials KW - Mesoporous materials KW - Mycoplasma KW - Sensors PY - 2013 DO - https://doi.org/10.1002/anie.201302954 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 52 IS - 34 SP - 8938 EP - 8942 PB - Wiley-VCH CY - Weinheim AN - OPUS4-28976 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fischer, Tobias A1 - Dietrich, Paul A1 - Streeck, C. A1 - Ray, S. A1 - Nutsch, A. A1 - Shard, A. A1 - Beckhoff, B. A1 - Unger, Wolfgang A1 - Rurack, Knut T1 - Quantification of variable functional-group densities of mixed-silane monolayers on surfaces via a dual-mode fluorescence and XPS label N2 - The preparation of aminated monolayers with a controlled density of functional groups on silica surfaces through a simple vapor deposition process employing different ratios of two suitable monoalkoxysilanes, (3-aminopropyl)diisopropylethoxysilane (APDIPES) and (3-cyanopropyl)dimethylmethoxysilane (CPDMMS), and advances in the reliable quantification of such tailored surfaces are presented here. The one-step codeposition process was carried out with binary silane mixtures, rendering possible the control over a wide range of densities in a single step. In particular, APDIPES constitutes the functional silane and CPDMMS the inert component. The procedure requires only small amounts of silanes, several ratios can be produced in a single batch, the deposition can be carried out within a few hours and a dry atmosphere can easily be employed, limiting self-condensation of the silanes. Characterization of the ratio of silanes actually bound to the surface can then be performed in a facile manner through contact angle measurements using the Cassie equation. The reliable estimation of the number of surface functional groups was approached with a dual-mode BODIPY-type fluorescence label, which allows quantification by fluorescence and XPS on one and the same sample. We found that fluorescence and XPS signals correlate over at least 1 order of magnitude, allowing for a direct linking of quantitative fluorescence analysis to XPS quantification. Employment of synchrotron-based methods (XPS; reference-free total reflection X-ray fluorescence, TXRF) made the traceable quantification of surface functional groups possible, providing an absolute reference for quantitative fluorescence measurements through a traceable measurement chain. KW - Oberflächenanalytik KW - Fluoreszenz KW - XPS KW - TXRF KW - Funktionelle Gruppen PY - 2015 DO - https://doi.org/10.1021/ac503850f SN - 0003-2700 SN - 1520-6882 VL - 87 IS - 5 SP - 2685 EP - 2692 PB - American Chemical Society CY - Washington, DC AN - OPUS4-34470 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gotor, Raúl A1 - Rurack, Knut A1 - Bell, Jérémy T1 - Fluorescent Paper Strips for the Detection of Diesel Adulteration with Smartphone Read-out N2 - Three fluorescent molecular rotors of 4-dimethylamino-4-nitrostilbene (4-DNS) were investigated for their potential use as viscosity probes to indicate the content of kerosene in diesel/kerosene blends, a wide-spread activity to adulterate fuel. In solvents with low viscosity, the dyes rapidly deactivate via a so-called twisted intramolecular charge transfer state, efficiently quenching the fluorescence. Measurements of diesel/kerosene blends revealed a good linear correlation between the decrease in fluorescence and the increase of the fraction of the less viscous kerosene in diesel/kerosene blends. Immobilization of the hydroxy derivative 4-DNS-OH in cellulose paper yielded test strips that preserve the fluorescent indicator's behavior. Combination of the strips with a reader based on a smartphone and a controlling app allowed to create a simple field test. The method can reliably detect the presence of kerosene in diesel from 7 to 100%, outperforming present standard methods for diesel adulteration. KW - Diesel KW - Kerosene KW - Adulteration KW - Fluorescent sensor KW - Smartphone KW - Test strips PY - 2018 UR - https://www.jove.com/video/58019 DO - https://doi.org/10.3791/58019 VL - 141 SP - e58019-1 EP - e58019-6 PB - MyJoVE Corporation CY - Cambridge, MA, USA AN - OPUS4-46567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maher, C. A1 - Schazmann, B. A1 - Gornushkin, Igor B. A1 - Rurack, Knut A1 - Gojani, Ardian T1 - Exploring an Application of Principal Component Analysis to LaserInduced Breakdown Spectroscopy of Stainless-Steel Standard Samples as a Research Project N2 - Laser-induced breakdown spectroscopy (LIBS) and principal component analysis (PCA) are frequently used for analytical purposes in research and industry, but they seldom are part of the chemistry Curriculum or laboratory exercises. This case study paper describes the combined application of LIBS and PCA during a research internship for an undergraduate student. The instructional method applied was based on a one-on-one mentorship, in which case the learner was engaged in a Research work. The learning activities included theoretical introductions to the LIBS and PCA methods, numerical simulation, experiments, and data analysis. The study covered three main topics: analysis of LIBS spectra, application of PCA for clustering, and use of PCA for experimental design. The realization of the study was instructive for all parties involved: from the mentorship point of view, it is concluded that the topics can be covered during an internship or developed into a one semester long research-based module of a chemistry program or a final year project. The student, on the other hand, developed profound technical skills in performing experiments and using PCA software for data analysis. KW - LIBS KW - PCA PY - 2021 DO - https://doi.org/10.1021/acs.jchemed.1c00563 VL - 98 SP - 3237 EP - 3244 PB - American Chemical Society Publications CY - USA AN - OPUS4-53515 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - García-Acosta, B. A1 - Comes, M. A1 - Bricks, J.L. A1 - Kudinova, M.A. A1 - Kurdyukov, V.V. A1 - Tolmachev, A.I. A1 - Descalzo López, Ana Belén A1 - Marcos, M. Dolores A1 - Martínez-Mánez, Ramon A1 - Moreno, A. A1 - Sancenón, F. A1 - Soto, J. A1 - Villaescusa, L.A. A1 - Rurack, Knut A1 - Barat, J. M. A1 - Escriche, I. A1 - Amorós, P. T1 - Sensory hybrid host materials for the selective chromo-fluorogenic detection of biogenic amines KW - Biogene Amine KW - Histamin KW - Farbreaktion KW - Pyralium-Farbstoffe KW - Fluoreszenz KW - Hybrid-Materialien PY - 2006 SN - 0022-4936 SN - 0009-241x SN - 1359-7345 SN - 1364-548x IS - 21 SP - 2239 EP - 2241 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-12563 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Y.-W. A1 - Descalzo López, Ana Belén A1 - Shen, Z. A1 - You, X.-Z. A1 - Rurack, Knut T1 - Dihydronaphthalene-fused Boron-dipyrromethene (BODIPY) dyes: insight into the electronic and conformational tuning modes of BODIPY fluorophones KW - Farbstoffe KW - Fluoreszenz KW - NMR-Spektroskopie KW - Synthese PY - 2012 DO - https://doi.org/10.1002/chem.201201081 SN - 0947-6539 SN - 1521-3765 VL - 18 IS - 23 SP - 7306 EP - 7309 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27113 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fery-Forgues, S. A1 - Delavaux-Nicot, B. A1 - Lavabre, D. A1 - Rurack, Knut T1 - Intermolecular quenching of excited singlet states by ferrocenyl derivatives - study with ketocyanine dyes N2 - The fluorescence quenching of 1,5-bis[4-(diethylamino)phenyl]penta-1,4-dien-3-one (1), 1-[4-(diethylamino)phenyl]-5-phenylpenta-1,4-dien-3-one (2) and chalcone 3 (1-[4-(diethylamino)phenyl]but-1-en-3-one) was studied in acetonitrile using ferrocene and three commercially available derivatives, 1,1?-diacetylferrocene, acetylferrocene and 1,1?-dimethylferrocene. The spectroscopic and electrochemical characteristics of all the compounds were investigated. The feasibility of the quenching process was calculated, showing in particular that electron transfer was thermodynamically possible in every case. The steady-state fluorescence of the three organic dyes was then measured in the presence and in the absence of the ferrocenyl derivatives and the data were corrected for inner-filter effects. 1,1?-Diacetylferrocene and acetylferrocene proved to be the most efficient quenchers, and among the three dyes investigated, chalcone 3 was the most sensitive to the presence of the ferrocenyl derivatives. However, the fluorescence decay times of the ketocyanines were not affected by the presence of the ferrocene derivatives, indicating that quenching was not diffusion-controlled but rather the consequence of the formation of a ground state complex. KW - Fluorescence KW - Ferrocene KW - Singlet state KW - Quenching KW - Energy transfer KW - Electron transfer PY - 2003 DO - https://doi.org/10.1016/S1010-6030(02)00400-8 SN - 1010-6030 SN - 1873-2666 VL - 155 IS - 1-3 SP - 107 EP - 114 PB - Elsevier CY - Lausanne AN - OPUS4-2277 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Descalzo López, Ana Belén A1 - Rurack, Knut T1 - On the signalling pathways and Cu(II)-mediated anion indication of N-meso-substituted heptamethine cyanine dyes N2 - Three mid-chain rigidified heptamethine cyanine dyes substituted with dimethylamino or cyclam groups at the meso position of the polymethine chain have been prepared and studied both experimentally and theoretically with respect to their spectroscopic response toward protons and various metal ions. Despite a potentially rich conformational ground-state chemistry, the spectroscopic studies revealed that the behaviour of the dyes is in agreement with Kuhn's classic polymethine dye theory. Coordination of metal ions and protonation of the alkyl amino groups in the cyclam moiety accordingly lead to moderate bathochromic shifts in absorption and reduced Stokes shifts. In contrast, protonation of the dimethylamino-substituted derivatives occurs at the polymethine chain, transforming the heptamethine into a trimethine-type chromophore with concomitant gigantic spectral blueshifts. In the presence of CuII in buffered aqueous solution, the cyclam-substituted dye selectively forms near-infrared absorbing aggregates. The latter allow the determination of citrate under realistic conditions by changes in absorption at wavelengths greater than 800 nm, which results from a disruption of the aggregates when citrate binds to CuII. The copper ions thus act as mediators in a signalling reaction that constitutes a colourimetric displacement assay. KW - Anions KW - Copper KW - Crown compounds KW - Dyes/pigments KW - Polymethines PY - 2009 DO - https://doi.org/10.1002/chem.200802087 SN - 0947-6539 SN - 1521-3765 VL - 15 IS - 13 SP - 3173 EP - 3185 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-19146 LA - eng 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 - The Supramolecular Chemistry of Organic-Inorganic Hybrid Materials N2 - The combination of nanomaterials as solid supports and supramolecular concepts has led to the development of hybrid materials with improved functionalities. These hetero-supramolecular ideas provide a means of bridging the gap between molecular chemistry, materials sciences, and nanotechnology. In recent years, relevant examples have been reported on functional aspects, such as enhanced recognition and sensing by using molecules on preorganized surfaces, the reversible building of nanometer-sized networks and 3D architectures, as well as biomimetic and gated chemistry in hybrid nanomaterials for the development of advanced functional protocols in three-dimensional frameworks. This approach allows the fine-tuning of the properties of nanomaterials and offers new perspectives for the application of supramolecular concepts. KW - Aggregation KW - Mesoporous materials KW - Molecular recognition KW - Nanoparticles KW - Sensors PY - 2006 DO - https://doi.org/10.1002/anie.200600734 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 45 IS - 36 SP - 5924 EP - 5948 PB - Wiley-VCH CY - Weinheim AN - OPUS4-12824 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xu, H.-J. A1 - Mack, J. A1 - Descalzo López, Ana Belén A1 - Shen, Z. A1 - Kobayashi, N. A1 - You, X.-Z. A1 - Rurack, Knut T1 - meso-Aryl phenanthroporphyrins: Synthesis and spectroscopic properties N2 - The successful synthesis of tetraphenyltetraphenanthroporphyrin (TPTPhenP; 5a) in 2006 under modified Rothemund–Lindsey conditions yielded a tetraphenyl porphyrinoid with a B band redshifted to an unprecedented 576 nm. Radially symmetric fused-ring expansion of tetraphenylporphyrin with phenanthrene moieties results in very deep saddling due to steric crowding and very marked redshifts of the Q and B (or Soret) porphyrinoid absorption bands. The extent to which the TPTPhenP structure can be further modified is explored, and the optical properties of TPTPhenPs are analyzed based on a perimeter model approach that makes use of time-dependent DFT calculations and magnetic circular dichroism spectroscopy and also based on a detailed analysis of the fluorescence emission. Attempts to introduce substituents at the ortho and meta positions of the meso-phenyl groups and to insert a central metal proved unsuccessful. The synthesis of a series of TPTPhenPs with strong electron-withdrawing (—CN, —NO2) and -donating (—CH3, —N(CH3)2) substituents at the para positions of the meso-phenyl rings is reported. Marked redshifts of the main spectral bands were consistently observed. The most pronounced spectral changes were observed with —N(CH3)2 groups (5i) due to a marked destabilization of the HOMO, which has large MO coefficients on the meso-carbon atoms. Protonation of 5i at both the ligand core and at the —N(CH3)2 groups resulted in unprecedented Q00 band absorption at wavelengths greater than 1200 nm. KW - Charge transfer KW - Circular dichroism KW - Dyes/pigments KW - Porphyrinoids KW - Protonation PY - 2011 DO - https://doi.org/10.1002/chem.201002596 SN - 0947-6539 SN - 1521-3765 VL - 17 IS - 32 SP - 8965 EP - 8983 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-24208 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Y.-W. A1 - Descalzo López, Ana Belén A1 - Shen, Z. A1 - You, X.-Z. A1 - Rurack, Knut T1 - Dihydronaphthalene-fused Boron-dipyrromethene (BODIPY) dyes: insight into the electronic and conformational tuning modes of BODIPY fluorophores N2 - A new series of boron-dipyrromethene (BDP, BODIPY) dyes with dihydronaphthalene units fused to the β-pyrrole positions (1 a-d, 2) has been synthesised and spectroscopically investigated. All the dyes, except pH-responsive 1 d in polar solvents, display intense emission between 550-700 nm. Compounds 1 a and 1 b with a hydrogen atom and a methyl group in the meso position of the BODIPY core show spectroscopic properties that are similar to those of rhodamine 101, thus rendering them potent alternatives to the positively charged rhodamine dyes as stains and labels for less polar environments or for the dyeing of latex beads. Compound 1 d, which carries an electron-donating 4-(dimethylamino)phenyl group in the meso position, shows dual fluorescence in solvents more polar than dibutyl ether and can act as a pH-responsive "light-up" probe for acidic pH. Correlation of the pKa data of 1 d and several other meso-(4-dimethylanilino)-substituted BODIPY derivatives allowed us to draw conclusions on the influence of steric crowding at the meso position on the acidity of the aniline nitrogen atom. Preparation and investigation of 2, which carries a nitrogen instead of a carbon as the meso-bridgehead atom, suggests that the rules of colour tuning of BODIPYs as established so far have to be reassessed; for all the reported couples of meso-C- and meso-N-substituted BODIPYs, the exchange leads to pronounced redshifts of the spectra and reduced fluorescence quantum yields. For 2, when compared with 1 a, the opposite is found: negligible spectral shifts and enhanced fluorescence. Additional X-ray crystallographic analysis of 1 a and quantum chemical modelling of the title and related compounds employing density functional theory granted further insight into the features of such sterically crowded chromophores. KW - Dyes/pigments KW - Fluorescent probes KW - Photophysics KW - Protonation KW - Boron PY - 2010 DO - https://doi.org/10.1002/chem.200902527 SN - 0947-6539 SN - 1521-3765 VL - 16 IS - 9 SP - 2887 EP - 2903 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-20957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Descalzo López, Ana Belén A1 - Xu, H.-J. A1 - Shen, Z. A1 - Rurack, Knut T1 - Red/Near-infrared Boron-Dipyrromethene Dyes as Strongly Emitting Fluorophores KW - BODIPY dyes KW - Near-infrared fluorophores KW - Fluorescent indicators KW - Charge transfer KW - Ring-fusion PY - 2008 DO - https://doi.org/10.1196/annals.1430.016 SN - 0077-8923 SN - 1749-6632 SN - 0094-8500 VL - 1130 SP - 164 EP - 171 PB - New York Academy of Sciences CY - New York, NY AN - OPUS4-17632 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Rurack, Knut T1 - Steady-State and Time-Resolved Spectroscopy of Ion-Sensitive Fluorescent Probes N2 - Im Mittelpunkt der vorliegenden Arbeit stehen Untersuchungen des spektroskopischen und komplexometrischen Verhaltens verschiedener Ionen-sensitiver Fluoreszenzsonden. Drei der vier Sondentypen folgen dabei einem herkömmlichen Prinzip zur Signalerzeugung und entsprechen in ihrem molekularen Aufbau einem fluoreszierenden Liganden (BP(OH)2 ) bzw. sogenannten intrinsischen Ladungstransfer-(ICT)- Fluoreszenzsonden (Donor-Akzeptor-substituierte Chalkone) und Elektronentransfer-(ET)-Fluoreszenzsonden (substituierte Triaryl-Δ2-pyrazoline). Die beiden letzten Systeme sind modular konzipiert, so dass signalgebender Fluorophor und komplexierender Rezeptor gezielt modellierbar sind. Im Fall der ICT-Sonden sind beide Einheiten elektronisch konjugiert, bei den ET-Sonden sind sie dagegen elektronisch weitgehend entkoppelt und das Signal wird durch Beeinflussung eines weitreichenden Elektronentransferprozesses generiert. Die Sonde vierten Typs, ein Bordipyrromethenderivat (BDP), ist ebenfalls modular aufgebaut. Bei ihr sind Fluorophor und Rezeptor aber nur durch den stark vorverdrillten Aufbau des Moleküls „virtuell“ entkoppelt. Neben diesem Einsatz eines alternativen Mechanismus zur Signalerzeugung standen vor allem die Steuerung der Selektivität durch gezielte Modifikation des Rezeptors sowie mögliche Verbesserungen der fluorometrischen Metallionenanalytik hinsichtlich Nachweisselektivität und -sensitivität durch Aufnahme zeitaufgelöster Fluoreszenzspektren (TRES) im Vordergrund der Untersuchungen. Unter Zuhilfenahme einer Reihe von Modellsubstanzen, NMR spektroskopischer Messmethoden und quantenchemischer Rechnungen wurden ausserdem allgemeine Erkenntnisse über das lichtinduzierte Verhalten der einzelnen Farbstoffklassen gewonnen. Der fluoreszierende Ligand BP(OH)2 zeigt, analog seiner Mutterverbindung 2,2‘-Bipyridyl, komplexierungsinduzierte Änderungen in seinem Absorptions- und Fluoreszenzverhalten bei Anwesenheit von Übergangs- und Schwermetallionen. Während paramagnetische Ionen wie CuII oder NiII (und auch HgII) zur statischen Fluoreszenzlöschung führen, bilden die diamagnetischen Ionen ZnII und CdII stark fluoreszierende Komplexe mit einer ionenspezifischen Fluoreszenzlebensdauer im ns-Zeitbereich. Beide Komplexe sind im angeregten Zustand stabil, was sich u. a. in einer, gegenüber dem freien Liganden stark herabgesetzten Geschwindigkeitskonstante für strahlungslose Desaktivierungsprozesse manifestiert. Die Absorptions- und Emissionsspektren der Komplexe überlappen stark und eine Unterscheidung mittels statischer Spektroskopie ist in beiden Fällen nur sehr begrenzt möglich. Die Trennung beider Komponenten gelingt allerdings unter Einsatz der zeitaufgelösten Fluoreszenzspektroskopie und an mehreren synthetischen ZnII/CdII-haltigen Proben konnte beispielhaft der Gewinn an Selektivität durch Aufnahme der TRES mit anschliessender global- analytischer Auswertung gezeigt werden. Die intrinsischen Fluoreszenzsonden des Chalkontyps tragen den Kationen-selektiven Rezeptor im Donorteil des Moleküls und zeigen bei Komplexierung durch Schwächung des Donors eine starke Abnahme des intramolekularen Ladungstransferprozesses. Im unkomplexierten Zustand erfolgt Fluoreszenz, je nach molekularem Aufbau und Polarität des Lösungsmittels, aus einem polaren direkt angeregten (E*) oder unter Einfachbindungsverdrillung und Reaktion im angeregten Zustand besetzten, hochpolaren Ladungstransferzustand (A*). Als konkurrierende Prozesse spielen dabei mögliche Besetzungen eines nicht fluoreszierenden, polaren (K*) bzw. schwach polaren (P*) Übergangszustandes eine Rolle. Des Weiteren ist in diesem Farbstoffsystem die Möglichkeit der Fluoreszenzlöschung durch benachbarte, tiefliegende nπ* Zustände (in unpolaren Lösungsmitteln) sowie durch verstärkte interne Konversion aufgrund des geringen energetischen Abstandes von Grund und angeregtem Zustand (in hochpolaren Lösungsmitteln) gegeben. Bei Kationenkomplexierung in polaren Lösungsmitteln wird vor allem, wie oben angedeutet, der Donor abgeschwächt, und es kommt zu einer moderaten Fluoreszenzverstärkung. Neben der erhöhten Fluoreszenzquantenausbeute resultiert der Effekt in Ionen-spezifischen Fluoreszenzlebensdauern der Komplexe. Durch den Austausch eines Stickstoff-Sauerstoff- gegen einen Stickstoff-Schwefel-Makrozyklus im Rezeptorteil des Systems konnte die Ionenselektivität von den Alkali- und Erdalkalimetallionen zu den thiophilen Metallionen AgI und HgII umgeleitet werden, wobei insbesondere die Fluoreszenzverstärkung in Gegenwart des herkömmlich als Fluoreszenzlöscher bekannten HgII-Ions analytisch wertvoll ist. Die ET-Sonden des Triaryl-Δ2-pyrazolin-Typs zeigen gegenüber den ICT-Sonden nur geringe spektrale Effekte, die Ioneninduzierte Fluoreszenzverstärkung ist dagegen wesentlich größer. Durch den gezielten Einsatz der unterschiedlichen Rezeptoren lassen sich hier ebenfalls die Selektivitäten steuern. In vergleichenden Untersuchungen konnten für die 5-p-N,NDialkylanilino-3-benzthiazol-1-phenyl-Δ2-pyrazoline die intramolekularen Prozesse charakterisiert werden, die Fluoreszenzlöschung im unkomplexierten und ein „Anschalten“ der Fluoreszenz im gebundenen Zustand bewirken. In diesen Molekülen findet der intramolekulare Ladungstransfer im Hauptchromophor im sub-ps Bereich statt und wird in hochpolaren Lösungsmitteln durch einen Elektronentransferprozess auf der ps-Zeitskala vom weitgehend elektronisch entkoppelten Rezeptor zum Akzeptorteil des Hauptchromophors gelöscht. Die „virtuelle“ Entkopplung von Fluorophor und Rezeptor im BDP-Derivat ermöglicht schließlich die Erzeugung von sehr grossen Fluoreszenzverstärkungssignalen bei Komplexierung. In diesen stark vorverdrillten Donor- Akzeptor-Biarylen geht der direkt angeregte emittierende Zustand (LE) in polaren Lösungsmitteln in einen hochpolaren, verdrillten radikalionischen Ladungstransferzustand (CT) über. Emission aus letzterem ist stark verboten und erfolgt, je nach Lösungsmittelpolarität, (weit) rotverschoben zur Fluoreszenz des LE, so dass schon in mittelpolaren Lösungsmitteln eine weithin getrennte, duale Fluoreszenz zu beobachten ist. In hochpolaren Lösungsmitteln sind beide Fluoreszenzen nahezu vollständig gelöscht. Metallionenkomplexierung führt zur Unterbrechung des CT-Prozesses und somit zu einem „Anschalten“ der LE- Emission mit Fluoreszenzverstärkungsfaktoren > 1000. Dieser Prozess ist dabei so sensitiv, dass für die meisten Kationenkomplexe zwei spektral sehr stark überlappend absorbierende und emittierende Komplexkonformere anhand ihrer Fluoreszenzlebensddauer unterschieden werden können. N2 - The present work is focused on the study of the spectroscopic and complexometric behavior of different ion-sensitive fl uorescent probes. Three of the four types of probes studied follow a conventional principle of signal generation and their molecular constitution corresponds to either a fl uorescent ligand ( BP(OH)2), so-called intrinsic charge transfer (ICT) fl uorescent probes (donor- acceptor-substituted chalcones), or electron transfer (ET) fl uorescent probes (substituted triaryl-Δ2- pyrazolines). The latter two systems are designed in a modular way and thus, both the signal generating fl uorophore and the complexing receptor can be carefully tuned. Whereas in the case of the ICT probes both units are electronically conjugated, these moieties are more or less electronically decoupled in the ET probes and signal generation is based on the modifi cation of a long range electron transfer process. The fourth type of probe investigated, a boron dipyrromethene derivative (BDP), is also designed in a modular way. But here, due to the highly pretwisted constitution of the molecule, fl uorophore and receptor are only “virtually” decoupled. Besides employing this alternative mechanism of signal generation, control of the selectivity by carefully directed receptor design and improvement of the selectivity and sensitivity of fl uorometric metal ion analysis by recording time resolved emission spectra (TRES) were the main aims of these investigations. Furthermore, with the aid of various model compounds, NMR spectroscopy as well as quantum chemical calculations, a fundamental understanding of the photophysical behavior of the different classes of dyes was obtained. In accordance with its parent compound 2,2‘- bipyridyl, the fl uorescent ligand BP(OH)2 shows complexation induced changes of its absorption and emission behavior in the presence of heavy and transition metal ions. Whereas paramagnetic ions such as CuII or NiII (and also HgII) lead to static fl uorescence quenching, the diamagnetic ions ZnII and CdII form strongly fl uorescent complexes with ion specifi c fl uorescence lifetimes in the ns time range. Both complexes are stable in the excited state which is manifested by a strongly reduced rate constant of non radiative deactivation compared to that of the free ligand. Both the absorption and emission spectra of the complexes largely overlap and a discrimination with steady-state fl uorometry is very limited. Nevertheless, with time resolved fl uorometry a separation of both components is possible and for a series of synthetic ZnII/CdII containing samples this gain in selectivity by global analysis of the time resolved emission spectra (TRES) could be demonstrated. The intrinsic fl uorescent probes of chalcone type contain a cation selective receptor in the donor part of the molecule and show a strong decrease of the intramolecular charge transfer process due to complexation induced weakening of the donor. Depending on molecular probe design and solvent polarity, the fl uorescence of the uncomplexed molecule occurs either from a polar directly exicted (E*) or a highly polar charge transfer state (A*) which is populated via an excited state reaction involving single bond twisting. Here, competing processes include population of a non emissive polar (K*) or weakly polar (P*) transient state. Furthermore, the fl uorescence of these dyes can be quenched by energetically close lying nπ* states (in apolar solvents) or by enhanced internal conversion due to the decreasing energy gap between ground and excited state (in highly polar solvents). As mentioned above, the donor strength is reduced upon cation complexation in polar solvents and a moderate fl uorescence enhancement occurs. Besides increased fl uorescence quantum yields, this effect results in ion specifi c fl uorescence lifetimes of the complexes. Upon exchanging the aza oxa for an aza thia macrocycle in the receptor part of the system, the cation selectivity could be tuned from alkali and alkaline earth metal ions to the thiophilic metal ions AgI and HgII. Here, especially the fl uorescence enhancement in the presence of the well-known quencher HgII is analytically valuable. Upon cation binding the ET probes of the triaryl-Δ2-pyrazoline type show very small spectral shifts but much larger fl uorescence enhancement compared to the ICT probes. Again, by problem specifi c use of different receptors, the selectivities can be controlled. Based on a detailed investigation, for the 5-p-N,N-dialkylanilino-3-benzthiazol-1-phenyl-Δ2-pyrazolines, the intramolecular processes which lead to fl uorescence quencing in the unbound state and “switching on” of the fl uorescence in the complexed state could be identifi ed. For these molecules, the intramolecular charge transfer in the basic chromophore occurs in the sub ps time range and is quenched by an electron transfer process from the largely electronically decoupled receptor to the acceptor part of the basic chromophore on the ps time scale in highly polar solvents. “Virtually” decoupling fl uorophore and receptor in the BDP derivative fi nally makes it possible to yield extremely high complexation induced fl uorescence enhancement signals. For these highly pretwisted donor acceptor biaryls, the directly excited emissive state (LE) forms a highly polar, twisted charge separated charge transfer state (CT) in polar solvents. Emission of the latter is strongly forbidden and, depending on solvent polarity, is largely red shifted compared to the LE fl uorescence. Thus, a largely separated dual fl uorescence is already observed in solvents of medium polarity and in highly polar solvents both fl uorescence bands are nearly completely quenched. Metal ion complexation blocks off the CT process and leads to a “switching on” of the LE emission yielding fl uorescence enhancement factors > 1000. This process is so sensitive that for most of the cation complexes studied, two emissive complex conformers with strongly overlapping absorption and emission spectra occur which could be distinguished by their fl uorescence lifetimes. T3 - BAM Forschungsberichtreihe - 235 PY - 2009 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-2150 SN - 978-3-89701-362-2 SN - 0938-5533 VL - 235 SP - 1 EP - 136 PB - Wirtschaftsverlag NW CY - Bremerhaven AN - OPUS4-215 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abdelshafi, Nahla A. A1 - Bell, Jérémy A1 - Rurack, Knut A1 - Schneider, Rudolf T1 - Microfluidic electrochemical immunosensor for the trace analysis of cocaine in water and body fluids N2 - Quick but accurate testing and on‐the‐spot monitoring of cocaine in oral fluids and urine continues to be an important toxicological issue. In terms of drug testing, a number of devices have been introduced into the market in recent decades, notably for workplace inspection or roadside testing. However, these systems do not always fulfill the requirements in terms of reliability, especially when low cut‐off levels are required. With respect to surface water, the presence of anthropogenic small organic molecules such as prescription and over‐the‐counter pharmaceuticals as well as illicit drugs like cannabinoids, heroin, or cocaine, has become a challenge for scientists to develop new analytical tools for screening and on‐site analysis because many of them serve as markers for anthropogenic input and consumer behavior. Here, a modular approach for the detection of cocaine is presented, integrating an electrochemical enzyme‐linked immunosorbent assay (ELISA) performed on antibody‐grafted magnetic beads in a hybrid microfluidic sensor utilizing flexible tubing, static chip and screen‐printed electrode (SPE) elements for incubation, recognition, and cyclic voltammetry measurements. A linear response of the sensor vs. the logarithm of cocaine concentration was obtained with a limit of detection of 0.15 ng/L. Within an overall assay time of 25 minutes, concentrations down to 1 ng/L could be reliably determined in water, oral fluids, and urine, the system possessing a dynamic working range up to 1 mg/L. KW - Cocaine PY - 2018 DO - https://doi.org/10.1002/dta.2515 VL - 11 SP - 492 EP - 500 PB - Wiley CY - Weinheim AN - OPUS4-48319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Descalzo López, Ana Belén A1 - Rurack, Knut ED - Abd-El Aziz, Alaa S. ED - Carraher, Charles E. ED - Pittman, Charles U. ED - Zeldin, Martel T1 - Supramolecular hybrid materials - integrating functionality with sensing 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 SN - 978-0-470-25144-7 SN - 1545-438X VL - 9 SP - 369 EP - 405 PB - John Wiley & Sons CY - Hoboken, New Jersey, USA AN - OPUS4-20318 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wan, Wei A1 - Descalzo, Ana B. A1 - Shinde, S. A1 - Weißhoff, Hardy A1 - Orellana, G. A1 - Sellergren, B. A1 - Rurack, Knut T1 - Ratiometric fluorescence detection of phosphorylated amino acids through excited-state proton transfer by using molecularly imprinted polymer (MIP) recognition nanolayers N2 - A 2,3-diaminophenazine bis-urea fluorescent probe monomer (1) was developed. It responds to phenylphosphate and phosphorylated amino acids in a ratiometric fashion with enhanced fluorescence accompanied by the development of a redshifted emission band arising from an excited-state proton transfer (ESPT) process in the hydrogen-bonded probe/analyte complex. The two urea groups of 1 form a cleft-like binding pocket (Kb>10^10 L^2 mol^-2 for 1:2 complex). Imprinting of 1 in presence of ethyl ester- and fluorenylmethyloxycarbonyl (Fmoc)-protected phosphorylated tyrosine (Fmoc-pTyr-OEt) as the template, methacrylamide as co-monomer, and ethyleneglycol dimethacrylate as crosslinker gave few-nanometer-thick molecularly imprinted polymer (MIP) shells on silica core microparticles with excellent selectivity for the template in a buffered biphasic assay. The supramolecular recognition Features were established by spectroscopic and NMR studies. Rational screening of comonomers and cross-linkers allowed to single out the best performing MIP components, giving significant imprinting factors (IF>3.5) while retaining ESPT emission and the ratiometric response in the thin polymer shell. Combination of the bead-based detection scheme with the phase-transfer assay dramatically improved the IF to 15.9, allowing sensitive determination of the analyte directly in aqueous media. KW - Core-shell particles KW - Excited-state proton transfer KW - Fluorescence KW - Molecular imprinting KW - Phosphorylated amino acids PY - 2017 DO - https://doi.org/10.1002/chem.201703041 SN - 1521-3765 SN - 0947-6539 VL - 23 IS - 63 SP - 15974 EP - 15983 PB - Wiley-VCH CY - Weinheim AN - OPUS4-43101 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sun, Yijuan A1 - Pérez-Padilla, Víctor A1 - Valderrey, Virginia A1 - Bell, Jérémy A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Fluorescence Detection of Perfluoroalkyl Carboxylic Acids with a Miniaturised Assay N2 - Per- and polyfluoroalkyl substances (PFAS) are a class of man-made organo-fluorine chemicals that have become environmental contaminants of emerging concern, originating from a variety of materials such as adhesive, stain- and oil-resistant coatings, firefighting foams, etc. The high strength of this C-F bond makes PFAS thermodynamically stable and resistant to (bio)degradation, thus retaining them in the environment over time. Perfluoroalkyl carboxylic acids (PFCAs), one category of the most used PFAS, consist of a fully fluorinated carbon backbone and a charged carboxylic acid headgroup, and have been classified as Substances of Very High Concern (SVHC) and added to the REACH Candidate List due to their persistence in the environment, non-biodegradability and toxicological effects.[1-2] Traditional techniques for the analysis of PFCAs include GC-MS, HRMS and HPLC-based approaches, which are laborious, not portable, costly and require trained personnel. In contrast, fluorescence assays can be designed as easy-to-operate, portable and cost-effective methods with high sensitivity and fast response. Integration of fluorescent probes with an adequately miniaturized assay enables a promising alternative for PFCAs analysis. Here, a novel guanidine fluorescent probe has been synthesized and fully characterized for the detection of PFCAs in a biphasic extract-&-detect assay. The fluorescent probe was then incorporated into polymeric matrices supported by a red dye-doped SiO2 nanoparticle to construct a dual-emission sensing platform. Such a system allows precise and selective detection of PFCAs, reducing the interference of competitors, matrix effects and other factors except for the PFCAs. The system was then employed in a droplet-based microfluidic setup which offers a portable and easy to operate detection platform. T2 - IMA 2023 CY - Chania, Greece DA - 18.09.2023 KW - PFAS KW - MIP KW - Fluorescence KW - Microfluidics KW - Fluorezsenz KW - Mikrofluidik PY - 2023 AN - OPUS4-58527 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bell, Jérémy A1 - Climent Terol, Estela A1 - Hecht, Mandy A1 - Buurman, Merwe A1 - Rurack, Knut T1 - Combining a droplet-based microfluidic tubing system with gated indicator releasing nanoparticles for mercury trace detection N2 - A droplet-based microfluidic sensor was developed for the detection of Hg2+ traces in water. The approach uses gated mesoporous nanoparticles loaded with a fluorescent BODIPY dye. The squaraine-based gating mechanism is highly selective for Hg2+ and the indicator release mechanism ensures sensitive detection. The microfluidic system is modular and was assembled from simple PTFE/PFA tubes, while detection was realized with standard optomechanic, optic, and electronic parts. The sensor shows a stable response without memory effects and allows the detection of Hg2+ in water down to 20 ppt. KW - Microfluidic sensor KW - Gated delivery system KW - Fluorescence KW - Mercury KW - Hybrid nanoparticles PY - 2016 DO - https://doi.org/10.1021/acssensors.5b00303 SN - 2379-3694 VL - 1 IS - 4 SP - 334 EP - 338 PB - American Chemical Society CY - Washington, DC AN - OPUS4-35831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wan, Wei A1 - Biyikal, Mustafa A1 - Wagner, R. A1 - Sellergren, B. A1 - Rurack, Knut T1 - Enantioselective fluorescence response of molecularly imprinted polymers (MIPs) toward carbobenzyloxy- (Cbz) protected amino acids N2 - Integration of a polymerisable fluorescent urea-nitrobenzoxadiazole monomer 1 into a few-nanometre thin molecularly imprinted polymer (MIP) shell coated onto a 300 nm silica core with the tetrabutylammonium salt of N-carbobenzyloxy-L-phenylalanine (Cbz- or Z-ʟ-Phe) as the imprinted template yields core/shell MIP nanoparticles that respond to the designated analyte with a strong fluorescence increase in the visible spectral range. The system shows promising imprinting and enantioselectivity factors of 3.6 and 1.9 when benzylmethylacrylate (BMA) is used as co-monomer and ethylene glycol dimethacrylate (EDMA) as cross-linker. A second, naphthalimide-based fluorescent urea 2 is employed in the preparation of MIP thin-films and monolithic polymers for separation techniques. Spectroscopic and chromatographic studies of the MIPs with the analytes Z-ʟ-Phe, Z-ʟ-glutamic acid (Z-ʟ-Glu) and penicilin G (PenG) revealed the (enantio)selective discrimination behaviour of these materials. T2 - 11. Dresdner Sensor Symposium 2013 CY - Dresden, Germany DA - 09.12.2013 KW - Enantioselectivity KW - Molecular imprinting KW - Fluorescence KW - Core-shell nanoparticles KW - Chromatography PY - 2013 SN - 978-3-9813484-5-3 DO - https://doi.org/10.5162/11dss2013/3.2 SP - 53 EP - 58 CY - Wunstorf AN - OPUS4-29818 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Vom Indikatormolekül zum Sensorpartikel - unterwegs zu leistungsfähigen miniaturisierten Analyseplattformen T2 - IGAS Jahreskolloquium CY - Berlin, Germany DA - 2008-11-10 PY - 2008 AN - OPUS4-18545 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - García-Acosta, B. A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Soto, J. A1 - Rurack, Knut A1 - Spieles, Monika A1 - García-Breijo, E. A1 - Gil, L. T1 - Ditopic N-Crowned 4-(p-Aminophenyl)-2,6-diphenylpyridines: Implications of Macrocycle Topology on the Spectroscopic Properties, Cation Complexation, and Differential Anion Responses N2 - A family of N-crowned 4-p-(aminophenyl)-2,6-diphenylpyridines DA (1-6) has been synthezised, characterized, and studied as potential hosts for the signaling of cationic and anionic guests. The ditopic probes contain two coordination sites, a monodentate 2,6-diphenylpyridine and an anilino group with macrocycles of different ring size, denticity, and type of secondary heteroatom (O and/or S). X-ray structure analysis of aza-oxa-thia-crowned 5 indicated a largely planar chromophore. Optical spectroscopic and electrochemical studies revealed that the anilino-type donor (D) and the 2,6-diphenylpyridine acceptor (A) are strongly -conjugated, entailing intense intramolecular charge-transfer absorption bands at 340 nm. Binding studies with protons and metal ions (M = Cu2+, Zn2+, Hg2+, Fe3+, Pb2+, Ni2+, Cd2+) showed shifts of the band to the visible (440 nm) when coordination at the pyridine group occurs, strengthening its acceptor character. In contrast, no band in the visible is formed if binding takes place at the anilino group. Three different responses were found for various pairs of DA and M: selective metal coordination to D or A as well as coordination at both sites. A selective response was found for 5 and Hg2+. Because of the multitude of coordination-induced effects, the DA-M ensembles were further employed for differential anion sensing. In this protocol, the addition of an anion X to a certain, weakly coordinated DA-M can (i) lead to the formation of a ternary ion pair complex (DA-M-X), (ii) change the preference for A or D coordination, (iii) induce dissociation of the complex, or (iv) can have no effect. Various patterns of absorption changes were obtained as a result of different responses (i)-(iv) of the DA-M's in the presence of various X's. Data analysis yielded recognition patterns for acetate, F- and CN-, demonstrating the potential of simple chromogenic host-guest pairs for differential anion signaling. KW - Fluoreszenz KW - Absorption KW - Molekular Logik KW - Farbstoffe PY - 2007 DO - https://doi.org/10.1021/ic062069z SN - 0020-1669 SN - 1520-510X VL - 46 IS - 8 SP - 3123 EP - 3135 PB - American Chemical Society CY - Washington, DC AN - OPUS4-16084 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Cooperativity and Simultaneity in Chemical Signaling via Luminescence T2 - I. Santa Maria Workshop on Chemistry, Devoted to Supramolecular Chemistry CY - Havana, Cuba DA - 2002-07-01 PY - 2002 AN - OPUS4-2963 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lozano-Torres, B. A1 - Marcos, M. Dolores A1 - Pardo, T. A1 - Sancenón, F. A1 - Martínez-Mánez, Ramon A1 - Rurack, Knut T1 - Anilinopyridine–metal complexes for the selective chromogenic sensing of cyanide anion N2 - Probe 1, which contains an anilinopyridine chromophore and an azaoxa macrocyclic subunit, presented an absorption band centered at 340 nm in acetonitrile. Addition of Fe(III), Cr(III) and Hg(II) induced the growth of a new absorption band at 430 nm (with color change from colorless to yellow), whereas in the presence of Cu(II), Zn(II) and Pb(II), less marked changes were observed. The color changes observed upon addition of Fe(III), Cr(III) and Hg(II) were ascribed to the formation of 1:1 stoichiometry complexes with probe 1. Coordination of Fe(III), Cr(III) and Hg(II) with the pyridine fragment of 1 induced an enhancement of the charge transfer character accompanied with a marked bathochromic shift that was reflected in a color change from colorless to yellow. The strength of the interaction between probe 1 and Fe(III) cation was modulated upon interaction with anions. Of all the anions tested, only cyanide was able to induce the bleaching of the yellow 1·Fe(III) complex solution. This bleaching was ascribed to the formation of 1·Fe(III)-CN complex that restored, to some extent, the optical features of the free probe allowing the chromogenic sensing of cyanide. Besides, 1·Fe(III) complex was used to detect cyanide in acetonitrile-water 90:10 v/v mixtures with good recoveries. KW - Anilinopyridine KW - Charge Transfer KW - Iron Complex KW - Colorimetric Test KW - Cyanide PY - 2018 DO - https://doi.org/10.1080/00958972.2018.1434719 SN - 0095-8972 VL - 71 IS - 6 SP - 786 EP - 796 PB - Taylor & Francis Group CY - London AN - OPUS4-45398 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bell, Jérémy A1 - Climent, Estela A1 - Gotor, Raúl A1 - Tobias, Charlie A1 - Martin-Sanchez, Pedro M. A1 - Rurack, Knut T1 - Dipstick coated with polystyrene-silica core-shell particles for the detection of microbiological fuel contamination N2 - Microbial contamination of fuels by fungi or bacteria poses risks such as corrosion and fuel system fouling, which can lead to critical problems in refineries and distribution systems and has a significant economic impact at every stage of the process. Many factors have been cited as being responsible for microbial growth, like the presence of water in the storage tanks. In fact, only 1 % water in a storage system is sufficient for the growth of microorganisms like bacteria or yeasts, as well as for the development of fungal biomass at the oil/water interface. This work presents a rapid test for the accurate determination of genomic DNA from aqueous fuel extracts. The detection is based on the use of polystyrene-mesoporous silica core-shell particles onto which modified fluorescent molecular beacons are covalently grafted. These beacons contain in the hairpin loop a target sequence highly conserved in all bacteria, corresponding to a fragment of the 16S ribosomal RNA subunit. The designed single-stranded molecular beacon contained fluorescein as an internal indicator and a quencher in its proximity when not hybridized. Upon hybridization in presence of the target sequence, the indicator and the quencher are spatially separated, resulting in fluorescence enhancement. To perform the assay the developed particles were deposited on different glass fibre strips to obtain a portable and sensitive rapid test. The assays showed that the presence of genomic DNA extracts from bacteria down to 50–70 μg L–1 induced a fluorescence response. The optical read-out was adapted for on-site monitoring by fitting a 3D-printed case to a conventional smartphone, taking advantages of the sensitivity of the CMOS detector. Such embedded assembly enabled the detection of genomic DNA in aqueous extracts down to the mg L–1 range and represents an interesting step toward on-site monitoring of fuel contamination. T2 - IMA 2023 CY - Chania, Greece DA - 18.09.2023 KW - Teststreifen KW - Test strip KW - Microbial KW - Mikrobiell KW - Smartphone KW - Particles KW - Partikeln PY - 2023 AN - OPUS4-58526 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Descalzo López, Ana Belén A1 - Zhu, Shengchao A1 - Fischer, Tobias A1 - Rurack, Knut ED - Demchenko, A.P. T1 - Optimization of the coupling of target recognition and signal generation N2 - Fluorescent reporters that literally "light up" upon binding of a target species are particularly interesting from an analytical point of view. This contribution introduces the main signaling concepts in fluorescent probe research, discusses strategies toward their optimization in terms of signal output, and highlights the wealth of alternative protocols that has been realized in the past two decades to create signaling systems with luminescence amplification features. KW - Dyes KW - Fluorescence KW - FRET KW - Molecular Recognition KW - Nanoparticles PY - 2010 SN - 978-3-642-04699-5 DO - https://doi.org/10.1007/978-3-642-04701-5_2 N1 - Serientitel: Springer Series on Fluorescence – Series title: Springer Series on Fluorescence VL - 9 IS - 1 SP - 41 EP - 106 PB - Springer AN - OPUS4-21941 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Fluorescent MIP (Molecularly Imprinted Polymer) Sensor Materials T2 - 1st International Caparica Conference on Chromogenic and Emissive Materials CY - Lisbon, Portugal DA - 2014-09-08 PY - 2014 AN - OPUS4-31354 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Novel Modular Sensors: Design of Efficient Probes for Various Analytes Utilizing the Phenoxazinone Chromophore T2 - Tag der Chemie CY - Potsdam, Germany DA - 2004-07-07 PY - 2004 AN - OPUS4-5353 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Monte, Christian T1 - Metallionen auf der Spur KW - Fluoreszenzsonden KW - Schwermetalle KW - Übergangsmetalle KW - Faseroptik PY - 2006 SN - 0344-1733 SN - 1610-8256 IS - 1/2 SP - 20 EP - 22 PB - Vogel CY - Würzburg AN - OPUS4-12179 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ros-Lis, J.V. A1 - Martínez-Mánez, Ramon A1 - Rurack, Knut A1 - Sancenón, F. A1 - Soto, J. A1 - Spieles, Monika T1 - Highly Selective Chromogenic Signaling of Hg2+ in Aqueous Media at Nanomolar Levels Employing a Squaraine-Based Reporter N2 - A chromogenic chemosensor for Hg2+ detection in aqueous media at the nanomolar level has been developed from squaraine scaffoldings. KW - Quecksilber KW - Absorption KW - Fluoreszenz KW - Squarain-Farbstoffe KW - Aggregate KW - Chromoionophor PY - 2004 DO - https://doi.org/10.1021/ic049422q SN - 0020-1669 SN - 1520-510X VL - 43 IS - 17 SP - 5183 EP - 5185 PB - American Chemical Society CY - Washington, DC AN - OPUS4-4124 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Kollmannsberger, M. A1 - Daub, J. T1 - Molekulares Schalten im nahen Infrarot (NIR) mit einem funktionalisierten Bordipyrromethen-Farbstoff KW - Molekularer Schalter KW - Solvatochromie KW - Donor-Akzeptor-System KW - Elektrochromie PY - 2001 DO - https://doi.org/10.1002/1521-3757(20010119)113:2<396::AID-ANGE396>3.0.CO;2-W SN - 0044-8249 SN - 0932-2140 SN - 1521-3757 VL - 113 IS - 2 SP - 396 EP - 399 PB - Wiley-VCH CY - Weinheim AN - OPUS4-1077 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Climent Terol, Estela A1 - Gotor, Raul A1 - Tobias, Charlie A1 - Bell, Jérémy A1 - Martin-Sanchez, Pedro A1 - Rurack, Knut T1 - Dip Sticks Embedding Molecular Beacon-Functionalized Core−Mesoporous Shell Particles for the Rapid On-Site Detection of Microbiological Fuel Contamination N2 - Microbial contamination of fuels by fungi and bacteria presents risks of corrosion and fuel system fouling. In this work, a rapid test for the determination of microbial genomic DNA from aqueous fuel extracts is presented. It combines test strips coated with polystyrene core/mesoporous silica shell particles, to the surface of which modified fluorescent molecular beacons are covalently grafted, with a smartphone detection system. In the hairpin loop, the beacons incorporate a target sequence highly conserved in all bacteria, corresponding to a fragment of the 16S ribosomal RNA gene, which is also present to a significant extent in the 18S rRNA gene of fungi, allowing for broadband microbial detection. In the developed assay, the presence of genomic DNA extracts from bacteria and fungi down to ca. 20−50 μg L−1 induced a distinct fluorescence response. The optical read-out was adapted for on-site monitoring by combining a 3D-printed case with a conventional smartphone, taking advantage of the sensitivity of contemporary complementary metal oxide semiconductor (CMOS) detectors. Such an embedded assembly allowed to detect microbial genomic DNA in aqueous extracts down to ca. 0.2−0.7 mg L−1 and presents an important step toward the on-site uncovering of fuel contamination in a rapid and simple fashion. KW - Bacteria KW - Fungi KW - Rapid test KW - Fluorescence KW - Smartphone KW - Biofouling PY - 2020 DO - https://doi.org/10.1021/acssensors.0c01178 SN - 2379-3694 VL - 6 IS - 1 SP - 27 EP - 34 PB - American Chemical Society CY - Washington, DC AN - OPUS4-51956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Sensory Molecularly Imprinted Polymers for the Selective Detection of Carboxylates through Fluorescence Modulation T2 - Europt(r)ode XII CY - Athens, Greece DA - 2014-04-13 PY - 2014 AN - OPUS4-30786 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shen, Z. A1 - Uno, H. A1 - Ono, N. A1 - Rurack, Knut A1 - Daub, J. T1 - Synthesis, electrochemical and spectroscopic studies on a new class of boron dipyrromethene based fluoroionophores PY - 2002 VL - 18 SP - 100 EP - 102 (Suppl. A) PB - Elsevier CY - Amsterdam AN - OPUS4-2082 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ros-Lis, J.V. A1 - Marcos, M. Dolores A1 - Martínez-Mánez, Ramon A1 - Rurack, Knut A1 - Soto, J. T1 - Ein regeneratives Chemodosimeter für die hoch selektive und empfindliche optische Bestimmung von Hg2+, basierend auf der metallinduzierten Bildung eines Farbstoffes KW - Fluorometrischer Nachweis KW - Chromogener Nachweis KW - Quecksilber KW - Chemodosimeter PY - 2005 SN - 0044-8249 SN - 0932-2140 SN - 1521-3757 VL - 117 IS - 28 SP - 4479 EP - 4482 PB - Wiley-VCH CY - Weinheim AN - OPUS4-10379 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ros Lis, J.V. A1 - Martínez-Mánez, Ramon A1 - Rurack, Knut A1 - Soto, J. T1 - A regenerative chemodosimeter based on metal-induced dye formation for the highly selective and sensitive optical detection of Hg2+ KW - Chemodosimeter KW - Chromogener Nachweis KW - Fluormetrischer Nachweis KW - Quecksilber PY - 2005 DO - https://doi.org/10.1002/anie.200500583 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 N1 - Sprachen: Deutsch/Englisch - Languages: German/English VL - 44 SP - 4405 EP - 4407 PB - Wiley-VCH CY - Weinheim AN - OPUS4-11006 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Kollmannsberger, M. A1 - Daub, J. T1 - Molecular Switching in the Near Infrared (NIR) with a Functionalized Boron-Dipyrromethene Dye PY - 2001 DO - https://doi.org/10.1002/1521-3773(20010119)40:2<385::AID-ANIE385>3.0.CO;2-F SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 40 IS - 2 SP - 385 EP - 387 PB - Wiley-VCH CY - Weinheim AN - OPUS4-1078 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Koval´chuk, A. A1 - Bricks, J.L. A1 - Slominskii, J.L. T1 - A simple bifunctional fluoroionophore signaling different metal ions either independently or cooperatively PY - 2001 DO - https://doi.org/10.1021/ja015560s SN - 0002-7863 SN - 1520-5126 VL - 123 SP - 6205 EP - 6206 PB - American Chemical Society CY - Washington, DC AN - OPUS4-1181 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 - Spieles, Monika A1 - Rurack, Knut T1 - Aquaraines as reporter units: insights into their photophysics, protonation, and metal-ion coordination behaviour KW - Dyes/pigments KW - Fluorescence KW - Metal ions KW - Protonation KW - Squaraines KW - Farbstoffe KW - Fluoreszenz KW - Metallionen KW - Protonierung PY - 2008 DO - https://doi.org/10.1002/chem.200800300 SN - 0947-6539 SN - 1521-3765 VL - 14 SP - 10101 EP - 10114 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-18444 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kovalchuck, Anton V. A1 - Bricks, Julia A1 - Reck, Günter A1 - Rurack, Knut A1 - Schulz, Burkhard A1 - Szumna, A. A1 - Weißhoff, Hardy T1 - A charge transfer-type fluorescent molecular sensor that "lights up" in the visible upon hydrogen bond-assisted complexation of anions PY - 2004 DO - https://doi.org/10.1039/b405207b SN - 0022-4936 SN - 0009-241x SN - 1359-7345 SN - 1364-548x SP - 1946 EP - 1947 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-4123 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bierstedt, Andreas A1 - Panne, Ulrich A1 - Rurack, Knut A1 - Riedel, Jens T1 - Characterization of two modes in a dielectric barrier discharge probe by optical emission spectroscopy and time-of-flight-mass spectrometry N2 - Among the large number of new ambient ionization schemes in the last few years, dielectric barrier discharge (DBD) has witnessed special attention. In this contribution a versatile dual mode DBD is introduced and characterized by means of optical emission spectroscopy and time-of-flight mass spectrometry. A direct comparison of the individual results from spectroscopy, spectrometry and transient current/voltage consumption gives evidence for the existence of two individual operational mechanisms. The first is driven by rapid transient changes in the potential difference between the two electrodes over time (usually denoted as the homogeneous mode), while the second is caused at high static potential differences (leading to filamentary discharges). The transient versus steady-state characteristics of the individual discharge origin suggest the driving force for the current flow to be inductive and capacitive, respectively. In most cases of dielectric barrier plasmas both discharge types coexist as competitive ion formation channels, however, detailed plasma characteristics of DBDs operated under different conditions allow for a clear distinction of the individual contributions. In this way, two characteristic product channels for the ionization of ambient water could be observed resulting in the generation of either preferentially protonated water clusters or ammonium water clusters. Careful tuning of the operation parameters of the discharge device allows an operation predominated by either of the two modes. As a consequence, facile switching into the desired operational mode results in either protonated molecules or ammoniated molecules of the analyte. Plasma characteristics for both moieties were evaluated and cross-correlated on the basis of several factors including: the production of reagent ions, the individual appearance of current/voltage profiles, UV/Vis spectroscopy, voltage and flux dependence and the individual response to test compounds. Although the filamentary mode has been already discussed in the literature to induce fragmentation processes, no experimental evidence for analyte dissociation could be found in the case of the test compounds used KW - Dual mode KW - Dielectric barrier discharge KW - Ambient desorption/ionization mass spectrometry KW - Emission spectroscopy KW - Ionization PY - 2015 DO - https://doi.org/10.1039/C5JA00332F SN - 0267-9477 SN - 1364-5544 VL - 30 IS - 12 SP - 2496 EP - 2506 PB - Royal Society of Chemistry CY - London AN - OPUS4-35092 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Calero, P. A1 - Hecht, Mandy A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Soto, J. A1 - Vivancos, J.L. A1 - Rurack, Knut T1 - Silica nanoparticles functionalised with cation coordination sites and fluorophores for the differential sensing of anions in a quencher displacement assay (QDA) N2 - In conjunction with quenching metal ions, silica nanoparticles carrying terpyridine coordination sites and sulforhodamine B signalling units were employed for the differential fluorometric recognition of anions. KW - Hybridmaterial KW - Silica-Nanopartikel KW - Fluoreszenz KW - Anionen KW - Verdrängungsassay PY - 2011 DO - https://doi.org/10.1039/c1cc13039k SN - 0022-4936 SN - 0009-241x SN - 1359-7345 SN - 1364-548x VL - 47 IS - 38 SP - 10599 EP - 10601 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-24489 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - On the Integration of Fluorescent Probes with Molecularly Imprinted Polymers for Powerful Sensor Materials N2 - Molecularly imprinted polymers (MIPs) are an established and powerful matrix for the selective enrichment and separation of chemical species, especially of small organic molecules. Because 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, they are frequently termed “artificial antibodies”. Compared to natural antibodies, they are chemically and physically much more robust. MIP formation proceeds through the polymerization of a mixture of functional monomers and cross-linkers in the presence of the template with subsequent extraction of the latter. While this strategy has been successfully employed for separation MIPs since decades, the development of sensory MIPs has long been limited to the combination of a MIP as enrichment phase with a separate signalling element in a discontinuous fashion, being unsuitable for many sensing applications. Only very recently, the implementation of specifically designed fluorescent probes into MIPs has been successfully accomplished, fluorescence being one of the most versatile, sensitive and easily miniaturizable techniques. This presentation will introduce basic design considerations, challenges, limitations and the potential that lies with such sensor materials on the background of the work carried out in our group. T2 - Bioinspired Materials 2017 CY - Manchester, UK DA - 31.08.2017 KW - Molecular imprinting KW - Dyes KW - Fluorescence KW - Sensing PY - 2017 AN - OPUS4-42260 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ros Lis, J.V. A1 - Martínez-Mánez, Ramon A1 - Rurack, Knut A1 - Soto, J. T1 - A regenerative chemodosimeter based on metal-induced dye formation for the highly selective and sensitive optical detection of Hg2+ KW - Fluormetrischer Nachweis KW - Chromogener Nachweis KW - Quecksilber KW - Chemodosimeter PY - 2005 DO - https://doi.org/10.1002/ange.200500583 SN - 0044-8249 SN - 0932-2140 SN - 1521-3757 VL - 117 SP - 4479 EP - 4482 PB - Wiley-VCH CY - Weinheim AN - OPUS4-7282 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Climent Terol, Estela A1 - Marcos, D. A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Soto, J. A1 - Rurack, Knut A1 - Amorós, P. T1 - The determination of methylmercury in real samples using organically capped mesoporous inorganic materials capable of signal amplification KW - Chemosensors KW - Fluorescence KW - Mesoporous materials KW - Methylmercury KW - Methylquecksilber KW - Sensoren KW - Mesoporöse Materialien KW - Fluoreszenz KW - Hybridmaterialien PY - 2009 DO - https://doi.org/10.1002/anie.200904243 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 48 IS - 45 SP - 8519 EP - 8522 PB - Wiley-VCH CY - Weinheim AN - OPUS4-20308 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martínez-Mánez, Ramon A1 - Sancenón, F. A1 - Hecht, Mandy A1 - Biyikal, Mustafa A1 - Rurack, Knut T1 - Nanoscopic optical sensors based on functional supramolecular hybrid materials N2 - This review highlights how the combination of supramolecular principles and nanoscopic solid structures enables the design of new hybrid sensing ensembles with improved sensitivity and/or selectivity and for the targeting of analytes for which selectivity is hard to achieve by conventional methods. Such ideas are bridging the gap between molecules, materials sciences and nanotechnology. Relevant examples will be detailed, taking into account functional aspects such as (1) enhanced coordination of functionalized solids, (2) enhanced signalling through preorganization, (3) signalling by assembly–disassembly of nanoscopic objects, (4) biomimetic probes utilizing discrimination by polarity and size and (5) distinct switching and gating protocols. These strategies are opening new prospects for sensor research and signalling paradigms at the frontier between nanotechnology, smart materials and supramolecular chemistry. KW - Supramolecular chemistry KW - Optical probes KW - Nanotechnology KW - Hybrid organic-inorganic materials PY - 2011 DO - https://doi.org/10.1007/s00216-010-4198-2 SN - 1618-2642 SN - 1618-2650 VL - 399 IS - 1 SP - 55 EP - 74 PB - Springer CY - Berlin AN - OPUS4-22908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, B. A1 - Haida, P. A1 - Fink, F. A1 - Krahl, T. A1 - Gawlitza, Kornelia A1 - Rurack, Knut A1 - Scholz, G. A1 - Kemnitz, E. T1 - Novel and easy access to highly luminescent Eu and Tb doped ultra-small CaF2, SrF2 and BaF2 nanoparticles – structure and luminescence N2 - A universal fast and easy access at room temperature to transparent sols of nanoscopic Eu3+ and Tb3+ doped CaF2, SrF2 and BaF2 particles via the fluorolytic sol–gel synthesis route is presented. Monodisperse quasi-spherical nanoparticles with sizes of 3–20 nm are obtained with up to 40% rare earth doping showing red or green luminescence. In the beginning luminescence quenching effects are only observed for the highest content, which demonstrates the unique and outstanding properties of these materials. From CaF2:Eu10 via SrF2:Eu10 to BaF2:Eu10 a steady increase of the luminescence intensity and lifetime occurs by a factor of ≈2; the photoluminescence quantum yield increases by 29 to 35% due to the lower phonon energy of the matrix. The fast formation process of the particles within fractions of seconds is clearly visualized by exploiting appropriate luminescence processes during the synthesis. Multiply doped particles are also available by this method. Fine tuning of the luminescence properties is achieved by variation of the Ca-to-Sr ratio. Co-doping with Ce3+ and Tb3+ results in a huge increase (>50 times) of the green luminescence intensity due to energy transfer Ce3+ → Tb3+. In this case, the luminescence intensity is higher for CaF2 than for SrF2, due to a lower spatial distance of the rare earth ions. KW - Luminescence materials KW - Alkaline earth metal fluorides KW - Fluorolytic sol–gel synthesis PY - 2017 DO - https://doi.org/10.1039/C6DT04711D VL - 46 IS - 9 SP - 2925 EP - 2936 PB - Royal Society of Chemistry AN - OPUS4-39286 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Röhr, Holger A1 - Trieflinger, C. A1 - Rurack, Knut A1 - Daub, J. T1 - Proton- and Redox-Controlled Switching of Photo- and Electrochemiluminescence in Thiophenyl-Substituted Boron-Dipyrromethene Dyes N2 - A luminescent molecular switch in which the active thiol/disulfide switching element is attached to a meso-phenyl-substituted boron-dipyrromethene (BDP) chromophore as the signalling unit is presented. The combination of these two functional units offers great versatility for multimodal switching of luminescence: 1) deprotonation/protonation of the thiol/thiolate moiety allows the highly fluorescent meso-p-thiophenol-BDP and its nonfluorescent thiolate analogue to be chemically and reversibly interconverted, 2) electrochemical oxidation of the monomeric dyes yields the fluorescent disulfide-bridged bichromophoric dimer, also in a fully reversible process, and 3) besides conventional photoexcitation, the well separated redox potentials of the BDP also allow the excited BDP state to be generated electrochemically (i.e., processes 1) and 2) can be employed to control both photo- and electrochemiluminescence (ECL) of the BDP). The paper introduces and characterizes the various states of the switch and discusses the underlying mechanisms. Investigation of the ortho analogue of the dimer provided insight into potential chromophore-chromophore interactions in such bichromophoric architectures in both the ground and the excited state. Comparison of the optical and redox properties of the two disulfide dimers further revealed structural requirements both for redox switches and for ECL-active molecular ensembles. By employing thiol/disulfide switching chemistry and BDP luminescence features, it was possible to create a prototype molecular ensemble that shows both fully reversible proton- and redox-gated electrochemiluminescence. KW - Boron-dipyrromethene KW - Electrochemiluminescence KW - Fluorescence KW - Molecular switches KW - Redox chemistry KW - Thiol/disulfide chemistry KW - Fluoreszenz KW - Elektrochemilumineszenz KW - Redox-Kontrolle KW - Molekulare Sensoren PY - 2006 DO - https://doi.org/10.1002/chem.200500729 SN - 0947-6539 SN - 1521-3765 VL - 12 IS - 3 SP - 689 EP - 700 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-12175 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Kollmannsberger, M. A1 - Daub, J. T1 - A highly efficient sensor molecule emitting in the near infrared (NIR): 3,5-distyryl-8-(p-dimethylaminophenyl)-difluoroboradiaza-s-indacene N2 - The spectroscopic properties and the photophysical behaviour of difluoroboradiaza-s-indacene 1, especially designed for the near infrared (NIR) spectral region and equipped with a p-dimethylaminophenyl group at the meso-position, were studied by steady-state and time-resolved optical spectroscopy. Solvent-dependent measurements revealed that for 1, excited state deactivation is governed by population of a non-emissive charge transfer excited state (1CT) as the solvent polarity increases, whereas reference compound 2 shows strong fluorescence from a locally excited state (1LE) in all the solvents employed. Accordingly, protonation of 1 completely suppresses the quenching excited state charge transfer process and leads to strong enhancement of fluorescence in the NIR, distinguishing 1 as a very sensitive fluorescent sensor molecule for pH or solvent acidity in this favourable wavelength region. PY - 2001 DO - https://doi.org/10.1039/b007379m SN - 0398-9836 VL - 25 SP - 289 EP - 292 PB - Le Centre National de la Recherche Scientifique CY - Paris AN - OPUS4-1085 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut T1 - Flipping the light switch 'ON' - the design of sensor molecules that show cation-induced fluorescence enhancement with heavy and transition metal ions N2 - Real-time and real-space analysis of heavy and transition metal ions employing fluorescent sensor molecules has received much attention over the past few years. Since many of these cations possess intrinsic properties that usually quench the fluorescence of organic dye molecules, a lot of research has lately been devoted to designing fluorescent probes that show complexation-induced fluorescence enhancement. Such an analytical reaction would be highly desirable in terms of increased sensitivity and selectivity. However, in this particular field of sensor research, the photophysical and photochemical mechanisms involved as well as the chemical constitutions of the sensor molecules employed are rather diverse and up to now, very few attempts have been made to establish some general concepts for rational probe design. By analyzing various systems published by other researchers as well as own work, this contribution aims at an elucidation of some of the underlying principles of heavy and transition metal ion-enhanced emission. KW - Fluorescent probes KW - Molecular recognition KW - Fluorescence enhancement KW - Fluorescence quenching KW - Heavy metal ions KW - Transition metal ions PY - 2001 DO - https://doi.org/10.1016/S1386-1425(01)00492-9 SN - 1386-1425 SN - 0370-8322 SN - 1873-3557 SN - 0584-8539 VL - 57 IS - 11 SP - 2161 EP - 2195 PB - Elsevier CY - Amsterdam AN - OPUS4-1182 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Towards simple and efficient molecular reporters by combining electron and/or charge transfer processes in fluorescent bifunctional dyes T2 - 57th Southwest Regional Meeting CY - San Antonio, TX, USA DA - 2001-10-17 KW - Donor-Acceptor-Systems KW - Heterocycles KW - Electron Transfer KW - Fluorescence KW - Chelates PY - 2001 VL - 57 SP - 1(?) EP - 2(?) AN - OPUS4-1183 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut T1 - Fluoreszenzmarker für Schwer- und Übergangsmetallionen: Selektivität durch gezieltes Rezeptordesign und Ionen-spezifische Fluoreszenzverstärkung KW - Fluoreszenzmarker KW - Schwermetalle KW - Rezeptoren PY - 2000 SN - 0937-1478 SN - 1521-3811 VL - 54 IS - 6 SP - 148 EP - 149 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-1050 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Bricks, J. L. A1 - Reck, Günter A1 - Schulz, Burkhard A1 - Spieles, Monika T1 - Cation coordination of bisamidopyridine-derived receptors as investigated in the solid-state and in solution N2 - A bisamidopyridine-type receptor, N,N'-bis(6-methyl-2-pyridyl)pyridine-2,6-dicarboxamide (1), and its CoIII complex were prepared and their X-ray structures were compared to those of N,N'-diphenylpyridine-2,6-dicarboxamide (2) and CoIII(2)2. Introduction of the two additional coordinative groups resulted in second-order interactions between the central ion and the nitrogen atoms of the terminal pyridine moieties in the crystalline state. Solution studies in acetonitrile revealed the importance of these interactions for the ligand's metal ion recognition ability. Whereas 2 only binds to PbII and CuII, 1 yields complexes with a majority of the heavy and transition metal ions studied, CoII, NiII, CuII, ZnII, FeIII, FeII, HgII, and PbII, respectively. The cation binding properties in solution were investigated by absorption spectroscopy and in the case of 1-MII/III, the formation of two spectroscopically distinguishable types of complexes was found. Protonation experiments and theoretical considerations helped to gain further insight into possible modes of coordination in solution. KW - Pyridine carboxamides KW - Ion recognition KW - Crystal structure KW - N-coordination PY - 2003 DO - https://doi.org/10.1080/1061027031000078239 SN - 1061-0278 SN - 1029-0478 VL - 15 IS - 3 SP - 189 EP - 197 PB - Gordon and Breach Science Publ. CY - New York, NY AN - OPUS4-2106 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Descalzo, Ana B. A1 - Martínez-Mánez, Ramon A1 - Radeglia, Reiner A1 - Rurack, Knut A1 - Soto, J. T1 - Coupling Selectivity with Sensitivity in an Integrated Chemosensor Framework: Design of a Hg2+-Responsive Probe, Operating above 500 nm N2 - For the highly selective and sensitive sensing of Hg2+ in water, a new design concept was realized where the selectivity of the probe's binding site is amplified by electronic properties of the chromophore. The molecular architecture of this phenoxazinone-type sensor molecule combines two potential coordination sites via an amino-keto conjugative backbone. These structural prerequisites allow only the most preferred mercuric ion to bind to the dithia dioxa monoaza crown unit, while other heavy, transition, and main group metal ions as well as protons are trapped at the keto group, inducing opposite spectral effects due to interaction with either the donor (Hg2+) or the acceptor group (other cations) of the probe. Besides these advantageous features, the probe operates well within the visible range of the spectrum and displays rather intense molar absorptivities as well as fluorescence quantum yields. PY - 2003 DO - https://doi.org/10.1021/ja0290779 SN - 0002-7863 SN - 1520-5126 VL - 125 IS - 12 SP - 3418 EP - 3419 PB - American Chemical Society CY - Washington, DC AN - OPUS4-2377 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Danel, A. A1 - Rotkiewicz, K. A1 - Grabka, D. A1 - Spieles, Monika A1 - Rettig, W. T1 - 1,3-Diphenyl-1H-pyrazolo[3,4-b]quinoline - A Versatile Fluorophore for the Design of Brightly Emissive Molecular Sensors N2 - The 1,3-diphenyl-1H-pyrazolo[3,4-b]-quinoline chromophore is a versatile building block for the construction of brightly fluorescent molecular sensors. Facile synthetic procedures allow integration of the chromophore into fluorophore-spacer-receptor systems as well as fluoroionophores operating via intramolecular charge transfer. Whereas the former photoinduced electron-transfer probes show strong analyte-induced fluorescence enhancement, the latter exhibit bright ratiometric dual emission. Employing prototype macrocyclic receptors, the favorable signaling features for metal ion recognition are demonstrated. PY - 2002 DO - https://doi.org/10.1021/ol027025i SN - 1523-7060 SN - 1523-7052 VL - 4 IS - 26 SP - 4647 EP - 4650 PB - American Chemical Society CY - Washington, DC AN - OPUS4-2107 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - García-Acosta, B. A1 - Albiach-Martí, X. A1 - García, E. A1 - Gil, R. A1 - Martínez-Mánez, Ramon A1 - Rurack, Knut A1 - Sancenón, F. A1 - Soto, J. T1 - Coordinative and electrostatic forces in action: from the design of differential chromogenic anion sensors to selective carboxylate recognition N2 - A new family of differential chromogenic anion chemosensors is described based on anilinopyridine–metal cation coordinative signalling ensembles KW - Differentielle Sensoren KW - Anionen KW - Carboxylat KW - Chromogene Sensoren KW - Koordinative Bindungen KW - Elektrostatische Wechselwirkungen PY - 2004 DO - https://doi.org/10.1039/b314997h SN - 0022-4936 SN - 0009-241x SN - 1359-7345 SN - 1364-548x IS - 7 SP - 774 EP - 775 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-3438 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fery-Forgues, S. A1 - Rurack, Knut A1 - Delavaux-Nicot, B. A1 - Lavabre, D. T1 - 1,3-Diphenyl-1H-pyrazolo[3,4-b]-quinoline (DPPQ)-a versatile fluorophore for the design of brightly emissive molecular sensors PY - 2002 SN - 1010-6030 SN - 1873-2666 PB - Elsevier CY - Lausanne AN - OPUS4-2108 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Bifunctional Molecular Reporters: Approaches towards Multi-Mode Fluorescence Signaling T2 - Gradulate College on Sensory Photoreceptors: "Sensory Photoreceptors in Natural and Artificial Systems" CY - Regensburg, Germany DA - 2002-01-09 PY - 2002 AN - OPUS4-2962 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Design Strategies for Efficient Fluorescent Molecular Sensors for Metal lons T2 - Workshop on Interactions between Biomolecules: From Chemistry to the Biological Target CY - Nimes, France DA - 2002-04-25 PY - 2002 AN - OPUS4-2964 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Einfache und effiziente Fluoro(metallo)ionophore auf der Basis von Elektronen- und Ladungstransferprozessen T2 - Universität Potsdam, Institut für Chemie CY - Potsdam, Germany DA - 2003-04-25 PY - 2003 AN - OPUS4-3757 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Simple and Efficient Fluoroionophores Based on Electron and/or Charge transfer Processes T2 - Polytechnische Universität Valencia, Institut für Chemie CY - Valencia, Spain DA - 2003-01-31 PY - 2003 AN - OPUS4-3758 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Macrocycles in a Different Light: The Influence of the Nature and Substitution Pattern of Heteroatoms on the Photophysics of Chromophore-Appended Crown Ethers T2 - 28th International Symposium on Macrocyclic Chemistry CY - Gdansk, Poland DA - 2003-07-13 PY - 2003 AN - OPUS4-4889 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - Intramolecular Charge-Transfer Characteristics of Fluorescent Donor-[Ethynyl-Donor]n (n=1,2) Dyads and Triads T2 - 8th Conference on Methods and Applications of Fluorescence: Spectroscopy, Imaging and Probes CY - Prague, Czech Republic DA - 2003-08-24 PY - 2003 AN - OPUS4-4894 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Trieflinger, C. A1 - Rurack, Knut A1 - Daub, J. T1 - "Turn ON/OFF your LOV light": Bordipyrromethen-Flavin-Dyaden als biomimetische, von der LOV-Domäne abgeleitete Schalter KW - Boron-dipyrromethene KW - Flavin KW - Thiol/disulfide KW - Fluorescence KW - Molecular switching KW - Photoreceptor mimicks PY - 2005 SN - 0044-8249 SN - 0932-2140 SN - 1521-3757 VL - 117 IS - 15 SP - 2328 EP - 2331 PB - Wiley-VCH CY - Weinheim AN - OPUS4-7305 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - A hybrid chemosensor material for the colorimetric and fluorometric detection of long-chain carboxylates T2 - 9th Conference on Methods and Applications of Fluorescence: Spectroscopy, Imaging and Probes CY - Lisbon, Portugal DA - 2005-09-04 PY - 2005 AN - OPUS4-7428 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rurack, Knut T1 - A Chromo- and Fluorogenic Hybrid Chemosensor Material for the Detection of Long-chain Carboxylates T2 - ANAKON 2005 CY - Regensburg, Germany DA - 2005-03-15 PY - 2005 AN - OPUS4-7427 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bricks, J.L. A1 - Kovalchuck, Anton V. A1 - Trieflinger, C. A1 - Nofz, Marianne A1 - Büschel, M. A1 - Tolmachev, A.I. A1 - Daub, J. A1 - Rurack, Knut T1 - On the Development of Sensor Molecules that Display FeIII-amplified Fluorescence N2 - Incorporation of a tailor-made size-restricted dithia-aza-oxa macrocycle, 1-oxa-4,10-dithia-7-aza-cyclododecane, via a phenyl linker into two fluorescent sensor molecules with electronically decoupled, rigidly fixed, and sterically preoriented architectures, a 1,3,5-triaryl-2-pyrazoline and a meso-substituted boron-dipyrromethene (BDP), yields amplified fluorescence in the red-visible spectral range upon binding of FeIII ions. The response to FeIII and potentially interfering metal ions is studied in highly polar aprotic and protic solvents for both probes as well as in neat and buffered aqueous solution for one of the sensor molecules, the BDP derivative. In organic solvents, the fluorescence of both indicators is quenched by an intramolecular charge or electron transfer in the excited state and coordination of FeIII leads to a revival of their fluorescence without pronounced spectral shifts. Most remarkably, the unbound BDP derivative shows dual emission in water and can be employed for the selective ratiometric signaling of FeIII in buffered aqueous solutions. KW - Fluoreszenz KW - Eisen KW - Fluoreszenzmarker PY - 2005 DO - https://doi.org/10.1021/ja050652t SN - 0002-7863 SN - 1520-5126 VL - 127 SP - 13522 EP - 13529 PB - American Chemical Society CY - Washington, DC AN - OPUS4-12180 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hennrich, G. A1 - Rurack, Knut A1 - Spieles, Monika T1 - Reconfiguration of the Symmetry and Charge-Transfer Characteristics of a Triply Crowned 1,3,5-Tris(arylalkynyl)mesitylene by Successive Metal Ion Complexation N2 - A triply benzocrown-ether-functionalized trialkynylmesitylene derivative with C3 symmetry as well as its linear analogue have been synthesized and their optical properties have been studied by UV/Vis absorption, steady-state and time-resolved fluorescencece spectroscopy. The spectroscopic investigation of the uncomplexed compounds revealed the nature of the electronic and excitonic communication pathway in the ground and excited states of the all-meta-substituted chromophore system. Upon cation complexation, the octopolar character of the free trialkynyl compound becomes dipolar and finally returns to octopolar in the fully complexed species. KW - Acetylenic scaffolding KW - Donor-acceptor systems KW - Fluorescence spectroscopy KW - UV/Vis spectroscopy KW - Supramolecular chemistry PY - 2006 DO - https://doi.org/10.1002/ejoc.200500595 SN - 1434-193X SN - 1099-0690 VL - 2006 IS - 2 SP - 516 EP - 521 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-12171 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Trieflinger, C. A1 - Röhr, Holger A1 - Rurack, Knut A1 - Daub, J. T1 - Multiples Schalten und photogesteuerte Elektrochemilumineszenz einer Dihydroazulen-Bordipyrromethen-Dyade KW - Bordipyrromethen KW - Elektrochemilumineszenz KW - Fluoreszenz KW - Molekulare Schalter KW - Photochromie PY - 2005 DO - https://doi.org/10.1002/ange.200501573 SN - 0044-8249 SN - 0932-2140 SN - 1521-3757 VL - 117 IS - 42 SP - 7104 EP - 7107 PB - Wiley-VCH CY - Weinheim AN - OPUS4-12172 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Trieflinger, C. A1 - Kovalchuck, Anton V. A1 - Daub, J. T1 - An ionically driven molecular IMPLICATION gate operating in fluorescence Mode N2 - An asymmetrically core-extended boron-dipyrromethene (BDP) dye was equipped with two electron-donating macrocyclic binding units with different metal ion preferences to operate as an ionically driven molecular IMPLICATION gate. A Na+-responsive tetraoxa-aza crown ether (R2) was integrated into the extended π system of the BDP chromophore to trigger strong intramolecular charge transfer (ICT2) fluorescence and guarantee cation-induced spectral shifts in absorption. A dithia-oxa-aza crown (R1) that responds to Ag+ was attached to the meso position of BDP in an electronically decoupled fashion to independently control a second ICT1 process of a quenching nature. The bifunctional molecule is designed in such a way that in the absence of both inputs, ICT1 does not compete with ICT2 and a high fluorescence output is obtained (InA=InB=0→Out=1). Accordingly, binding of only Ag+ at R1 (InA=1, InB=0) as well as complexation of both receptors (InA=InB=1) also yields Out=1. Only for the case in which Na+ is bound at R2 and R1 is in its free state does quenching occur, which is the distinguishing characteristic for the InA=0 and InB=1→Out=0 state that is required for a logic IMPLICATION gate and Boolean operations such as IF-THEN or NOT. KW - Charge transfer KW - Dyes/pigments KW - Fluorescence KW - Logic gates KW - Molecular devices PY - 2007 DO - https://doi.org/10.1002/chem.200700858 SN - 0947-6539 SN - 1521-3765 VL - 13 IS - 32 SP - 8998 EP - 9003 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-16085 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martínez, R. A1 - Sancenón, F. A1 - Hoffmann, Katrin A1 - Rurack, Knut A1 - Descalzo López, Ana Belén T1 - Materiales híbridos en química analítica N2 - El desarrollo de receptores sintéticos complejos basados en conceptos de la química supramolecular no garantiza en ocasiones un reconocimiento molecular selectivo. Una alternativa en ciertos aspectos más simple y prometedora es el empleo de materiales híbridos orgánico-inorgánicos preparados mediante la funcionalización de sólidos inorgánicos porosos con receptores sintéticos adecuados. El anclaje de estos sistemas coordinantes a un soporte sólido da lugar a ciertos efectos sinérgicos que no están presentes ni en el material inicial ni en el receptor por separado y que sugieren que estos nuevos materiales híbridos pueden ser empleados en el desarrollo de nuevos sensores y nuevos protocolos de reconocimiento molecular y/o iónico. The development of synthetic receptors based in supramolecular chemistry concepts will no allow a selective molecular recognition. A more simple, convenient and innovative approach relies on the use of organic-inorganic hybrid materials. These hybrid materials will be prepared by the grafting of certain synthetic receptors onto porous inorganic solids. The grafting of these coordinating systems onto a solid support leads to synergic effects that are hardly achievable with only the synthetic receptors or the solids alone. The presence of these synergic effects suggests that these organic-inorganic hybrid materials will be used for the development of novel sensory systems and novel molecular and/or ionic recognitionprotocols. KW - Soportes inorgánicos KW - Receptores sintéticos KW - Materiales híbridos KW - Efectos sinérgicos KW - Química analítica KW - Inorganic supports KW - Synthetic receptors KW - Hybrid materials KW - Synergic effects KW - Analytical chemistry PY - 2007 SN - 1575-3417 VL - 103 IS - 4 SP - 22 EP - 27 PB - Springer AN - OPUS4-17512 LA - spa AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wu, D. A1 - Descalzo López, Ana Belén A1 - Weik, F. A1 - Emmerling, Franziska A1 - Shen, Z. A1 - You, X.-Z. A1 - Rurack, Knut T1 - A core-modified Rubyrin with meso-aryl substituents and phenanthrene-fused pyrrole rings: a highly conjugated near-infrared dye and Hg2+ probe KW - Fluorescence KW - Mercury KW - NIR dyes KW - Porphyrinoids KW - Sensors PY - 2008 DO - https://doi.org/10.1002/Anie.200702854 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 47 IS - 1 SP - 193 EP - 197 PB - Wiley-VCH CY - Weinheim AN - OPUS4-16448 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 -