TY - JOUR A1 - Ramos, I. I. A1 - Carl, Peter A1 - Schneider, Rudolf A1 - Segundo, M. A. T1 - Automated lab-on-valve sequential injection ELISA for determination of carbamazepine N2 - The development of an automated miniaturized analytical system that allows for the rapid monitoring of carbamazepine (CBZ) levels in serum and wastewater is proposed. Molecular recognition of CBZ was achieved through its selective interaction with microbeads carrying anti-CBZ antibodies. The proposed method combines the advantages of the micro-bead injection spectroscopy and of the flow-based platform lab-on-valve for implementation of automatic immunosorbent renewal, rendering a new recognition surface for each sample. The sequential (or simultaneous) perfusion of CBZ and the horseradish peroxidase-labelled CBZ through the microbeads is followed by real-time on-column Monitoring of substrate (3,30,5,50-tetramethylbenzidine) oxidation by colorimetry. The evaluation of the initial oxidation rate and also the absorbance value at a fixed time point provided a linear response versus the logarithm of the CBZ concentration. Under the selected assay conditions, a single analysis was completed after only 11 min, with a quantification range between 1.0 and 50 µg L⁻¹. Detection of CBZ levels in undiluted wastewater samples was feasible after a simple filtration step while good recoveries were attained for spiked certified human serum, analyzed without sample clean-up. KW - Automation KW - Bead injection spectroscopy KW - Human serum KW - Microparticles KW - Therapeutic Drug Monitoring KW - Wastewater PY - 2019 DO - https://doi.org/10.1016/j.aca.2019.05.017 SN - 0003-2670 VL - 1076 SP - 91 EP - 99 PB - Elsevier CY - Amsterdam AN - OPUS4-48317 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Singh, Chandan A1 - Riedel, Soraya A1 - Konthur, Zoltán A1 - Hodoroaba, Vasile-Dan A1 - Radnik, Jörg A1 - Schenk, J. A. A1 - Schneider, Rudolf T1 - Functionalized Ti3C2Tx nanosheets based biosensor for point-of-care detection of SARS-CoV‑2 antigen N2 - MXenes are considered a promising class of two-dimensional materials with extraordinary physical and electrochemical properties. Distinguished features like high specific surface area and outstanding electrical conductivity make them suitable for electrochemical biosensing applications. Here, we report the development of a biosensor involving the functionalized MXene−titanium carbide nanosheets (Ti3C2Tx-NS) and monoclonal antibodies against the SARS-CoV-2 nucleocapsid protein (anti-SARS-CoV-2 mAb) to design a point-of-care device for detection of the SARS-CoV-2 nucleocapsid protein (SARS-CoV-2 NP) antigen. Few-layered titanium carbide nanosheets (denoted as FL-Ti3C2Tx-NS) have been synthesized using a single-step etching and delamination method and characterized using optical and electron microscopy techniques revealing the suitability for immunosensing applications. Binding studies revealed the excellent affinity between the biosensor and the SARS-CoV-2 NP. Electrochemical detection of SARS-CoV-2 NP is performed using differential pulse voltammetry and read by a smartphone-based user interface. The proposed FL-Ti3C2Tx-NS based biosensor offers the detection of SARS-CoV-2 NP with a limit of detection of 0.91 nM in a wide detection range in spiked saliva samples. Additionally, there is no cross-reactivity in the presence of potential interferants like SARS-CoV-2 spike glycoprotein and bovine serum albumin. These findings demonstrate the potential of MXenes in developing a rapid and reliable tool for SARS-CoV-2 NP detection. While we report the biosensing of SARS-CoV-2 NP, our system also paves the way for the detection of other SARS-CoV-2 antigens like spike protein or other biomolecules based on antigen−antibody interactions. KW - Antigen testing KW - Few-layered titanium carbide nanosheets KW - SARS-CoV-2 nucleocapsid protein KW - Label-free detection KW - Electrochemical immunosensor PY - 2023 DO - https://doi.org/10.1021/acsaenm.2c00118 SN - 2771-9545 N1 - Geburtsname von Riedel, Soraya: Höfs, S. - Birth name of Riedel, Soraya: Höfs, S. VL - 1 IS - 1 SP - 495 EP - 507 PB - American Chemical Society CY - Washington, DC AN - OPUS4-56931 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beyer, Sebastian A1 - Schürmann, Robin A1 - Feldmann, Ines A1 - Blocki, A. A1 - Bald, Ilko A1 - Schneider, Rudolf A1 - Emmerling, Franziska T1 - Maintaining Stable Zeolitic Imidazolate Framework (ZIF) Templates during Polyelectrolyte Multilayer Coating N2 - Equipping ZIF particles with a polyelectrolyte membrane provides functional groups at their interface, enabling further conjugations necessary for applications such as targeted drug delivery. Previous approaches to coat ZIF particles with polyelectrolytes led to surface corrosion of the template material. This work overcomes previous limitations by performing a Layer-by-Layer (LbL) polyelectrolyte coating onto ZIF-8 and ZIF-67 particles in nonaqueous environment. Using the 2-methylimidazolium salt of polystyrensulfonic acid instead of the acid itself and polyethyleneimine in methanol led to intact ZIF particles after polyelectrolyte coating. This was verified by electron microscopy. Further, zetapotential and atomic force microscopy measurements confirmed a continuous polyelectrolyte multilayer built up. The here reported adaption to the well-studied (LbL) polyelectrolyte selfassembly process provides a facile method to equip ZIF particles with a nanometer thin polyelectrolyte multilayer membrane. KW - Zeolithe KW - Molecular Organic Frameworks KW - MOF KW - ZIF KW - Layer-by-Layer KW - Beschichtung KW - Polyelektrolyt PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-447729 DO - https://doi.org/10.1016/j.colcom.2017.11.004 SN - 2215-0382 VL - 22 SP - 14 EP - 17 PB - Elsevier B.V. CY - Amsterdam, NL AN - OPUS4-44772 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pereira, P.M.R. A1 - Carvalho, José Joao A1 - Silva, S. A1 - Cavaleiro, J.A.S. A1 - Schneider, Rudolf A1 - Fernandes, R. A1 - Tomé, J.P.C. T1 - Porphyrin conjugated with serum albumins and monoclonal antibodies boosts efficiency in targeted destruction of human bladder cancer cells N2 - The synthesis of a novel PS conjugated with bovine and human serum albumin (BSA and HSA) and a monoclonal antibody anti-CD104 is reported, as well as their biological potential against the human bladder cancer cell line UM-UC-3. No photodynamic effect was detected when the non-conjugated porphyrin was used. Yet, when it was coupled covalently with the mAb anti-CD104, BSA and HSA, the resulting photosensitizer conjugates demonstrated high efficacy in destroying the cancer cells, the mAb anti-CD104 efficacy overruling the albumins. KW - Rinderserumalbumin KW - BSA KW - Monoklonale Antikörper KW - Blasenkrebs KW - Konjugate KW - Conjugates KW - Therapeutische Antikörper KW - CD104 PY - 2014 DO - https://doi.org/10.1039/c3ob42082e SN - 1477-0520 SN - 1477-0539 VL - 12 IS - 11 SP - 1804 EP - 1811 PB - RSC CY - Cambridge AN - OPUS4-30451 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Stephan A1 - Hanelt, S. A1 - Canitz, C. A1 - Hoffmann, Holger A1 - Garbe, L.-A. A1 - Schneider, Rudolf T1 - Entwicklung monoklonaler Antikörper gegen Diclofenac N2 - Diclofenac (DCF) wird als nicht-steroidales, antientzündliches Arzneimittel gegen Fieber, Entzündungen, rheumatische Erkrankungen und Schmerzen eingesetzt. 70 % werden nach Einnahme wieder ausgeschieden. Aufgrund unvollständiger Elimination in den Kläranlagen lassen sich Rückstände im Trinkwasser und im Oberflächengewässer nachweisen. Diclofenac wird in der Umweltanalytik v.a. mittels GC-MS oder LCMS nachgewiesen. Bioanalytische Methoden machen sich die spezifische Antigen-Antikörper-Wechselwirkung zunutze, so z.B. Immunoassays. Die hierfür erforderlichen Antikörper werden durch Immunisierung mit einem Konjugat aus dem Analyten und einem Trägerprotein gewonnen. Die Kopplung kann direkt über die Carboxylfunktion von Diclofenac erfolgen. Um Abschirmungseffekte zu vermeiden, kann zwischen Protein und Analy1 ein Spacer sinnvoll sein. PY - 2015 SN - 1618-3258 SN - 1617-5301 IS - 4 SP - 107 EP - 109 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-35241 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baldofski, Stefanie A1 - Hoffmann, Holger A1 - Lehmann, Andreas A1 - Breitfeld, Stefan A1 - Garbe, L.-A. A1 - Schneider, Rudolf T1 - Enzyme-linked immunosorbent assay (ELISA) for the anthropogenic marker isolithocholic acid in water N2 - Bile acids are promising chemical markers to assess the pollution of water samples with fecal material. This study describes the optimization and validation of a direct competitive enzyme-linked immunosorbent assay for the bile acid isolithocholic acid (ILA). The quantification range of the optimized Assay was between 0.09 and 15 mg/L. The assay was applied to environmental water samples. Most studies until now were focused on bile acid fractions in the particulate phase of water samples. In order to avoid tedious sample preparation, we undertook to evaluate the dynamics and significance of ILA levels in the aqueous phase. Very low concentrations in tap and surface water samples made a pre-concentration step necessary for this matrix as well as for wastewater treatment plant (WWTP) effluent. Mean recoveries for spiked water samples were between 97% and 109% for tap water and WWTP influent samples and between 102% and 136% for WWTP effluent samples. 90th percentiles of intra-plate and inter-plate coefficients of variation were below 10% for influents and below 20% for effluents and surface water. ILA concentrations were quantified in the range of 33-72 mg/L in influent, 21-49 ng/L in effluent and 18-48 ng/L in surface water samples. During wastewater Treatment the ILA levels were reduced by more than 99%. ILA concentrations of influents determined by ELISA and LC-MS/MS were in good agreement. However, findings in LC-ELISA experiments suggest that the true ILA levels in concentrated samples are lower due to interfering effects of matrix compounds and/or cross-reactants. Yet, the ELISA will be a valuable tool for the performance check and comparison of WWTPs and the localization of fecal matter input into surface waters. KW - ELISA KW - LC-MS/MS KW - Bile acids KW - Fecal marker KW - Surface water KW - Wastewater PY - 2016 DO - https://doi.org/10.1016/j.jenvman.2016.08.023 SN - 0301-4797 VL - 182 SP - 612 EP - 619 AN - OPUS4-37668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baldofski, Stefanie A1 - Canitz, C. A1 - Garbe, L.-A. A1 - Schneider, Rudolf T1 - Studies on the development of antibodies for the highly hydrophobic plasticizers DINCH and DEHT N2 - Diisononylcyclohexane-1,2-dicarboxylate (DINCH) and di-2-ethylhexyl terephthalate (DEHT), two of the most important substitutes for phthalate plasticizers, are used for a wide range of applications. Consequently, an increasing occurrence in urine and environmental samples is reported. Reliable and fast analytical methods for the quantification of these plasticizers are needed. So far, mainly GC-MS or LC-MS methods are used. We aimed to develop the first antibodies and immunoassays allowing for high-throughput analysis of samples. We designed two DINCH hapten structures and one DEHT hapten structure and employed hapten-protein conjugates for the immunization of rabbits. Sensitive competitive enzyme-linked immunosorbent assays (ELISAs) against each hapten using the produced polyclonal antibodies were established. Yet, binding of DINCH to the respective antibodies was not observed in neither direct nor indirect assay formats, even when using protein conjugates with the heterologous haptens and different carrier proteins in the indirect format. The use of surfactants and solvents in the sample buffer did not result in recognition of the plasticizers. Also, no binding of DEHT in ELISA employing the respective antibodies was detected. We speculate that the production of antibodies against these highly hydrophobic molecules is not possible via our route, however a different hapten design could overcome this obstacle. KW - Weichmacher KW - Phthalate KW - Antikörper KW - Selektivität KW - Ersatzstoffe KW - Polyclonal antibodies KW - Phthalate substitutes KW - Antibody production for hydrophobic molecules KW - DEHT KW - DINCH KW - Hapten design PY - 2018 DO - https://doi.org/10.1016/j.ab.2017.12.006 SN - 0003-2697 VL - 543 SP - 90 EP - 96 PB - Elsevier Inc. CY - Amsterdam, NL AN - OPUS4-44015 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Stephan A1 - Hoffmann, Holger A1 - Garbe, L.-A. A1 - Schneider, Rudolf T1 - Liquid chromatography-tandem mass spectrometry detection of diclofenac and related compounds in water samples N2 - A frequently studied environmental contaminant is the active substance diclofenac, which is removed insufficiently in sewage treatment plants. Since its inclusion in the watch list of the EU Water Framework Directive, the concentrations in surface waters will be determined throughout Europe. For this, still, more precise analytical methods are needed. As a reference, HPLC-MS is frequently employed. One of the major metabolites is 4’-hydroxydiclofenac (4’-OH-DCF). Also, diclofenac lactam is important for assessing degradation and transformation. Aceclofenac (ACF), the glycolic acid ester of diclofenac is used as a drug, too, and could potentially be cleaved to yield diclofenac again. In various sewage treatment plant influent samples, diclofenac, 4’-OH-DCF, DCF lactam and ACF could be determined with detection limits of 3 µg/L, 0.2 µg/L, 0.17 µg/L and 10 ng/L, respectively. KW - Diclofenac KW - Festphasenextraktion KW - HPLC-MS KW - Probenvorbereitung KW - Kläranlage KW - Abwasser KW - Zyklisierung KW - Diclofenac KW - Solid-phase extraction KW - Sewage treatment plant KW - Cyclization KW - Sample treatment KW - HPLC–MS PY - 2018 DO - https://doi.org/10.1016/j.chroma.2018.01.037 SN - 0021-9673 SN - 1873-3778 VL - 1538 SP - 112 EP - 116 PB - Elsevier B.V. CY - Amsterdam, NL AN - OPUS4-44183 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schneider, Rudolf A1 - Almeida, Ângela A1 - Calisto, V. A1 - Esteves, V.I. A1 - Soares, A.M.V.M. A1 - Figueira, E. A1 - Freitas, R. T1 - Toxicity associated to uptake and depuration of carbamazepine in the clam Scrobicularia plana under a chronic exposure N2 - Carbamazepine (CBZ) is an antiepileptic drug commonly detected in aquatic systems, with toxic effects to inhabiting organisms. Limited information is known on stress response biomarkers associated to bioconcentration and depuration of CBZ in aquatic organisms. Moreover, few studies addressed if the response and recovery of organisms to a contaminant can change when they are collected in a contaminated site. This study intended to understand the bioconcentration and depuration of CBZ combined with its toxicological impact in Scrobicularia plana clams collected from two contrasting areas (MIRA, Mira channel, non-contaminated and LAR, Laranjo bay, arithropogenically impacted) from the Ria de Aveiro (Portugal). The clams were exposed for 14 days to environmentally relevant CBZ concentrations (0.0, 4.0 and 8.0 mu g/L), followed by a 14 day depuration period. CBZ concentrations in S. plana tissues were rapidly bioconcentrated during the exposure period. In the depuration period CBZ was eliminated, in some extent. The main toxic effects occurred at the highest concentration (8.0 mu g/L) after 14 days of exposure in which the clams from LAR accumulated ahigher CBZ concentration (LAR: similar to 10 ng/g FW) than clams from MIRA (MIRA: similar to 7 ng/g FW). LAR clams exhibited higher oxidative damage at this concentration, demonstrated by higher LPO levels over time (increase of similar to 1.4% relative to control) and, in comparison with MIRA clams (LAR: 17.7 nmol/g FW; MIRA: 11.4 nmol/g FW). After the depuration period, LAR clams recovered from the stress induced by CBZ. A decrease in LPO for LAR (decrease of similar to 40% in relation to the end of the exposure period) was accompanied by a decrease in CBZ tissue concentrations (decrease of similar to 61% relative to the end of the exposure period). MIRA clams were not oxidatively injured (low LPO levels remained unchanged after the depuration and CBZ decreased similar to 80% relative to the end of the exposure period). KW - Invertebrates KW - Pharmaceutical drugs KW - Biomarkers KW - Oxidative stress PY - 2017 DO - https://doi.org/10.1016/j.scitotenv.2016.12.069 SN - 0048-9697 VL - 580 SP - 1129 EP - 1145 AN - OPUS4-43297 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schneider, Rudolf A1 - Schmidt, S. A1 - Hanelt, S. A1 - Canitz, C. A1 - Hoffmann, H. A1 - Garbe, L.-A. T1 - Synthetic Strategies for the Modification of Diclofenac N2 - For many heterogeneous sensor applications as well as the synthesis of hapten antigens to produce antibodies, protein conjugates of the target substance are essential. A requirement is that the target substance already offers or is modified to contain a functionality that allows for coupling to a protein, that is, an amino acid residue. Ideally, to avoid shielding of the compound by the carrier protein, a sufficient distance to the protein surface should be provided. With its carboxyl function diclofenac (DCF) allows for direct binding to lysine residues after in situ synthesis of the NHS ester. One problem is that diclofenac as free acid tends to autocondensation, which results in low yields. Here we describe the 'insertion' of a C6 spacer via synthesis of the amide with 6-aminohexanoic acid. To carry out the reaction in solution, first the methyl ester of the amino acid had to be produced. Due to otherwise low yields and large cleaning efforts, solid-phase synthesis on Fmoc Ahx Wang resin is recommended. The crude product is mainly contaminated by cleavage products from the resin which were removed by chromatography. The structure of the highly pure hapten was completely determined by nuclear magnetic resonance (NMR) spectroscopy. KW - Diclophenac KW - Hapten synthesis KW - Solid-phase synthesis PY - 2017 DO - https://doi.org/10.1055/s-0036-1588858 SN - 0936-5214 VL - 28 IS - 15 SP - 1984 EP - 1989 PB - Georg Thieme Verlag AN - OPUS4-43316 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kuhne, Maren A1 - Dippong, Martin A1 - Flemig, Sabine A1 - Hoffmann, Katrin A1 - Petsch, K. A1 - Schenk, J.A. A1 - Kunte, Hans-Jörg A1 - Schneider, Rudolf T1 - Comparative characterization of mAb producing hapten-specific hybridoma cells by flow cytometric analysis and ELISA N2 - A novel method that optimizes the screening for antibody-secreting hapten-specific hybridoma cells by using flow cytometry is described. Cell clones specific for five different haptens were analyzed. We selectively double stained and analyzed fixed hybridoma cells with fluorophore-labeled haptens to demonstrate the target-selectivity, and with a fluorophore-labeled anti-mouse IgG antibody to characterize the level of surface expression of membrane-bound IgGs. ELISA measurements with the supernatants of the individual hybridoma clones revealed that antibodies from those cells, which showed the highest fluorescence intensities in the flow cytometric analysis, also displayed the highest affinities for the target antigens. The fluorescence intensity of antibody-producing cells corresponded well with the produced antibodies' affinities toward their respective antigens. Immunohistochemical staining verified the successful double labeling of the cells. Our method makes it possible to perform a high-throughput screening for hybridoma cells, which have both an adequate IgG production rate and a high target affinity. KW - Immunization KW - Hapten KW - Monoclonal antibodies KW - Hybridoma KW - Flow cytometry KW - ELISA KW - Estradiol KW - Estrone KW - Digoxigenin KW - Zearalenone KW - Aflatoxin KW - CLSM PY - 2014 DO - https://doi.org/10.1016/j.jim.2014.07.004 SN - 0022-1759 SN - 1872-7905 VL - 413 SP - 45 EP - 56 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-32322 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -