TY - JOUR A1 - Burnage, Samual A1 - Bell, Jérémy A1 - Wan, Wei A1 - Kislenko, Evgeniia A1 - Rurack, Knut T1 - Combining a hybrid chip and tube microfluidic system with fluorescent molecularly imprinted polymer (MIP) core–shell particles for the derivatisation, extraction, and detection of peptides with N-terminating phosphorylated tyrosine N2 - The reliable identification and quantitation of phosphorylated amino acids, peptides and proteins is one of the key challenges in contemporary bioanalytical research, an area of particular interest when attempting to diagnose and treat diseases at an early stage. We have developed a synthetic probe for targeting phosphorylated amino acids, based on core–shell submicron-sized particles consisting of a silica core, coated with a molecularly imprinted polymer (MIP) shell. The MIP layer contains a fluorescent probe crosslinker which binds selectively to phosphorylated tyrosine (pY) moieties with a significant imprinting factor (IF) and responds with a "light-up” fluorescence signal. The bead-based ratiometric detection scheme has been successfully transferred to a microfluidic chip format and its applicability to rapid assays has been exemplarily shown by discriminating a pY-terminating oligopeptide against its nonphosphorylated counterpart. Such miniaturised devices could lead to an automated pY or pY N-terminated peptide measurement system in the future. The setup combines a modular microfluidic system for amino acid derivatisation, extraction (by micropillar co-flow) and selective adsorption and detection with the fluorescent MIP core–shell particle probes. A miniaturised optical assembly for low-light fluorescence measurements was also developed, based on miniaturised opto-electronic parts and optical fibres. The emission from the MIP particles upon binding of pY or pY N-terminated peptides could be monitored in real-time. KW - Microfluidics KW - Molecularly imprinted polymers KW - Phosphorylated peptides KW - Fluorescence KW - Core-shell particles PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569204 DO - https://doi.org/10.1039/d2lc00955b SN - 1473-0197 VL - 23 IS - 3 SP - 466 EP - 474 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-56920 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Garrido, E. A1 - Hernández-Sigüenza, G. A1 - Climent, Estela A1 - Marcos, M. D. A1 - Rurack, Knut A1 - Gaviña, P. A1 - Parra, M. A1 - Sancenón, F. A1 - Martí-Centelles, V. A1 - Martínez-Máñez, R. T1 - Strip-based lateral flow-type indicator displacement assay for γ-hydroxybutyric acid (GHB) detection in beverages N2 - The use of gamma-hydroxybutyric acid (GHB) in drug-facilitated sexual assault has increased due to its availability and high solubility in aqueous solutions and alcoholic beverages, necessitating the development of rapid methods for GHB detection. In this respect, portable testing methods for use in the field, based on lateral flow assays (LFAs) and capable of detecting trace concentrations of target analytes, are particularly attractive and hold enormous potential for the detection of illicit drugs. Using this strategy, here we report a rapid, low cost, easy-to-handle strip-based LFA for GHB analysis employing a smartphone for fluorescence readout. At molecular signalling level, the ensemble is based on a Cu2+ complex with a tetradentate ligand and the fluorescent dye coumarin 343, which indicate GHB through an indicator displacement assay (IDA) in aqueous solution. When incorporated in a LFA-based strip test this system shows a detection limit as low as 0.03 μM for GHB in MES buffer solution and is able to detect GHB at concentrations of 0.1 μM in soft drinks and alcoholic beverages in only 1 min. KW - Indicator displacement assay KW - Gamma-hydroxybutyric acid KW - Lateral flow assay KW - Test strip KW - Fluorescent dyes KW - Smartphone readout PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564631 DO - https://doi.org/10.1016/j.snb.2022.133043 SN - 0925-4005 VL - 377 SP - 1 EP - 7 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-56463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sjöberg, T. A1 - El-Schich, Z. A1 - Rurack, Knut A1 - Gjörloff Wingren, A. T1 - Colorectal Cancer Cell Spheroids Co-Cultured with Molecularly Imprinted Fluorescent Particles Targeting Sialic Acid Show Preserved Cell Viability N2 - In vitro cultured 3D models of CRC have been demonstrated to hold considerable worth in drug discovery, drug resistance analysis, and in studying cell-cell and cell-matrix interactions that occur in the tumor microenvironment. The 3D models resemble the in vivo physiological microenvironment by replicating the cell type composition and tissue architecture. Molecularly imprinted polymers (MIPs) have been investigated for use instead of antibodies against small nonimmunogenic structures, such as sialic acid (SA). Glyco-conjugates including SA are present on all cells, and often deregulated on cancer cells. Here, we present a novel approach for targeting and detecting colorectal cancer cells (CRC) by using in vitro cultured HT29 3D spheroids co-cultured in vitro with either fluorescent MIPs targeting SA, SA-MIPs, or the two lectins targeting SA, MAL I, and SNA. Both formaldehyde-fixed and viable HT29 3D spheroids with or without SA-MIPs were imaged in 3D by confocal microscopy. The results revealed a preserved cell morphology and viability of the HT29 3D spheroids co-cultured in vitro with SA-MIPs. However, the lectins MAL I and SNA targeting the alpha-2,3 or alpha-2,6 SA glycosidic linkages, respectively, affected the cell viability when co-cultured with the viable HT29 3D spheroids, and no living cells could be detected. Here, we have shown that the SA-MIPs could be used as a safe and low-cost diagnostic tool for targeting and detecting cancer cells in a physiologically relevant 3D cancer model in vitro. KW - Molecularly Imprinted Polymers KW - Durchflusszytometrie KW - Zellanalytik KW - Fluoreszenz KW - Mikroskopie PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573840 DO - https://doi.org/10.3390/app13095330 VL - 13 IS - 9 SP - 1 EP - 6 PB - MDPI CY - Basel AN - OPUS4-57384 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ritter, B. A1 - Krahl, T. A1 - Rurack, Knut A1 - Kemnitz, E. T1 - Nanoscale CaF2 doped with Eu3+ and Tb3+ through fluorolytic sol-gel synthesis N2 - In this article, the high potential of the fluorolytic sol–gel process to synthesize nanoscopic rare earth-doped calcium fluoride sols is shown. Through a fluorolytic sol–gel process we manage to achieve spherical monodisperse ~5 nm sized nanoparticles using a simple and reproducible one-pot-wet chemical route at room temperature. The as-synthesized clear sols exhibit an intense red and green luminescence under UV excitation at room temperature. A spectroscopic study of the sols revealed the characteristic transitions 5D0 → 7FJ of Eu3+ and 5D4 → 7FJ of Tb3+, with 5D0 → 7F2 (611 nm) of Eu3+ and 5D4 → 7F4 (581 nm) of Tb3+ as the most prominent transitions. This facile synthetic strategy is also valuable for developing other luminescent nanoparticles. KW - Calciumfluorid KW - Europium KW - Lumineszenz KW - Nanopartikel KW - Sol-Gel-Synthese KW - Terbium PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-320120 DO - https://doi.org/10.1039/c4tc01073f SN - 2050-7526 SN - 2050-7534 VL - 2 IS - 40 SP - 8607 EP - 8613 PB - Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-32012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bolz, Axel A1 - Panne, Ulrich A1 - Rurack, Knut A1 - Buurman, Merwe T1 - Glass fibre paper-based test strips for sensitive SERS sensing N2 - We present paper-based test strips for chemical sensing with surface enhanced Raman scattering as detection method. The test strips are prepared on glass fibre paper with silver nanoparticles and a spray method with an airbrush spray setup as a low cost fabrication approach. The properties of the test strips are investigated with three classical Raman analytes rhodamine 6G, 4-aminothiophenol and adenine and optimized for a good reproducibility of the intensity measurements. All test analytes can be identified at low concentrations. For adenine, a concentration series from 10⁻⁴ M to 10⁻⁸ M is measured and the calibration data can be fitted and evaluated with a Langmuir isotherm model. The optimized test strips are applied for the identification of two antibiotics enoxacin and enrofloxacin. KW - surface enhanced Raman scattering KW - glass fibre paper KW - sensing KW - spray KW - Langmuir isotherm PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-354878 DO - https://doi.org/10.1039/C5AY03096J SN - 1759-9660 VL - 8 IS - 6 SP - 1313 EP - 1318 PB - The Royal Society of Chemistry AN - OPUS4-35487 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lempke, L. A1 - Fischer, Tobias A1 - Bell, Jérémy A1 - Kraus, Werner A1 - Rurack, Knut A1 - Krause, N. T1 - Gold-catalyzed allene cycloisomerization for pyrrole synthesis: towards highly fluorinated BODIPY dyes N2 - A novel synthetic strategy toward highly fluorinated BODIPY dyes with exceptional photostabilities relying on sustainable gold catalysis has been developed. A key to the tailored pyrrole precursors is the gold catalysis performed in ionic liquids as the reaction medium, allowing a facile recycling of the catalysts. The dyes prepared are well-matching with the spectral windows of popular rhodamine dyes and possess high brightness while showing a distinctly higher photostability than the rhodamines especially in aprotic solvents. KW - Gold-Katalyse KW - BODIPY-Farbstoffe KW - Photostabilität KW - Fluor-Substitution KW - Fluoreszenz PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-344692 DO - https://doi.org/10.1039/c4ob02671c SN - 1477-0520 SN - 1477-0539 VL - 13 IS - 12 SP - 3787 EP - 3791 PB - RSC CY - Cambridge AN - OPUS4-34469 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pascual, L. A1 - Baroja, I. A1 - Aznar, E. A1 - Sancenón, F. A1 - Marcos, M. Dolores A1 - Murguía, J.R. A1 - Amorós, P. A1 - Rurack, Knut A1 - Martínez-Mánez, Ramon T1 - Oligonucleotide-capped mesoporous silica nanoparticles as DNA-responsive dye delivery systems for genomic DNA detection N2 - New hybrid oligonucleotide-capped mesoporous silica nanoparticles able to detect genomic DNA were designed. KW - Gesteuerte Materialien KW - Mycoplasma KW - Mesoporöse Träger KW - Sonden KW - DNA PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-321357 UR - http://pubs.rsc.org/en/content/articlepdf/2015/cc/c4cc08306g DO - https://doi.org/10.1039/C4CC08306G SN - 0022-4936 SN - 0009-241x SN - 1359-7345 SN - 1364-548x VL - 51 IS - 8 SP - 1414 EP - 1416 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-32135 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Climent Terol, Estela A1 - Rurack, Knut A1 - Hecht, Mandy T1 - Loading and Release of Charged and Neutral Fluorescent Dyes into and from Mesoporous Materials: A Key Role for Sensing Applications N2 - The aim of this study is to determine the efficiency of loading and release of several zwitterionic, neutral, anionic and cationic dyes into/from mesoporous nanoparticles to find the optimum loading and release conditions for their application in detection protocols. The loading is carried out for MCM-41 type silica supports suspended in phosphate-buffered saline (PBS) buffer (pH 7.4) or in acetonitrile, involving the dyes (rhodamine B chloride, rhodamine 101 chloride, rhodamine 101 perchlorate, rhodamine 101 inner salt, meso-(4-hydroxyphenyl)-boron–dipyrromethene (BODIPY), sulforhodamine B sodium salt and fluorescein 27). As a general trend, rhodamine-based dyes are loaded with higher efficiency, when compared with BODIPY and fluorescein dyes. Between the rhodamine-based dyes, their charge and the solvent in which the loading process is carried out play important roles for the amount of cargo that can be loaded into the materials. The delivery experiments carried out in PBS buffer at pH 7.4 reveal for all the materials that anionic dyes are more efficiently released compared to their neutral or cationic counterparts. The overall best performance is achieved with the negatively charged sulforhodamine B dye in acetonitrile. This material also shows a high delivery degree in PBS buffer. KW - Mesoporous materials KW - Charged dyes KW - Neutral dyes KW - Dye loading optimisation KW - Dye release PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522596 UR - https://www.mdpi.com/2072-666X/12/3/249 DO - https://doi.org/10.3390/mi12030249 VL - 12 IS - 3 SP - 249 PB - MDPI AN - OPUS4-52259 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kimani, Martha Wamaitha A1 - Beyer, S. A1 - El-Schich, Z. A1 - Gawlitza, Kornelia A1 - Rurack, Knut A1 - Gjörloff-Wingren, A. T1 - Imprinted Particles for Direct Fluorescence Detection of Sialic Acid in Polar Media and on Cancer Cells with Enhanced Control of Nonspecific Binding N2 - Glycoproteins are abundant on the cell surface of mammals, providing structural support, modulating cell Membrane properties, and acting as signaling agents. Variation of glycosylation patterns has been found to indicate various disease states, including cell malignancy. Sialic acid (SA) is present as a terminating group on cell-surface glycans, and its overexpression has been linked to several types of cancer. Detection of SA on the cell surface is therefore critical for detection of cancer in its early stages. In this work, a fluorescent molecularly imprinted polymer layer targeting SA was synthesized on the surface of silica-coated polystyrene (PS) particles. Compared to previous works, a PS core supplies a lighter, lower-density support for improved suspension stability and scattering properties. Moreover, their smaller size provides a higher surface-area-to-volume ratio for binding. The incorporation of a fluorescent monomer in the MIP shell allowed for simple and rapid determination of binding specificity in polar media due to a deprotonation−reprotonation interaction mechanism between the fluorescent monomer and SA, which led to spectral changes. Upon titration of the MIP particles with SA in suspension, an increase in fluorescence emission of the particles was observed, with the MIP particles binding SA more selectively compared to the nonimprinted polymer (NIP) control particles. In cell staining experiments performed by flow cytometry, the binding behavior of the MIP particles compared favorably with that of SA-binding lectins. NIPs prepared with a “dummy” template served as a better negative control in cell binding assays due to the favorable inward orientation of template-binding functional groups in the polymer shell, which reduced nonspecific binding. The results show that fluorescent MIPs targeting SA are a promising tool for in vitro fluorescence staining of cancerous cells and for future diagnosis of cancer at early stages. KW - Flow cytometry KW - Sialic acid KW - Fluorescence KW - Molecularly imprinted polymers KW - Cancer cells PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525216 DO - https://doi.org/10.1021/acsapm.0c01353 VL - 3 IS - 5 SP - 2363 EP - 2373 PB - American Chemical Society AN - OPUS4-52521 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Li, Q. A1 - Shinde, S. A1 - Grasso, G. A1 - Caroli, A. A1 - Abouhany, R. A1 - Lanzillotta, M. A1 - Pan, G. A1 - Wan, Wei A1 - Rurack, Knut A1 - Sellergren, B. T1 - Selective detection of phospholipids using molecularly imprinted fluorescent sensory core-shell particles N2 - Sphingosine-1-phosphate (S1P) is a bioactive sphingo-lipid with a broad range of activities coupled to its role in G-protein coupled receptor signalling. Monitoring of both intra and extra cellular levels of this lipid is challenging due to its low abundance and lack of robust affinity assays or sensors. We here report on fluorescent sensory core-shell molecularly imprinted polymer (MIP) particles responsive to near physiologically relevant levels of S1P and the S1P receptor modulator fingolimod phosphate (FP) in spiked human serum samples. Imprinting was achieved using the tetrabutylammonium (TBA) salt of FP or phosphatidic acid (DPPA·Na) as templates in combination with a polymerizable nitrobenzoxadiazole (NBD)-urea monomer with the dual role of capturing the phospho-anion and signalling its presence. The monomers were grafted from ca 300 nm RAFT-modified silica core particles using ethyleneglycol dimethacrylate (EGDMA) as crosslinker resulting in 10–20 nm thick shells displaying selective fluorescence response to the targeted lipids S1P and DPPA in aqueous buffered media. Potential use of the sensory particles for monitoring S1P in serum was demonstrated on spiked serum samples, proving a linear range of 18–60 μM and a detection limit of 5.6 μM, a value in the same range as the plasma concentration of the biomarker. KW - Molecularly imprinted polymers KW - Phospholipids KW - Fluorescence KW - Dye monomers PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509485 DO - https://doi.org/10.1038/s41598-020-66802-3 SN - 2045-2322 VL - 10 IS - 1 SP - 9924 PB - Nature Research CY - London AN - OPUS4-50948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -