TY - CONF A1 - Carl, Peter A1 - Schneider, Rudolf A1 - Sarma, Dominik A1 - Rurack, Knut T1 - A wash-free, multiplex microbead assay for determination of emerging bioactive compounds in wastewater N2 - Pollutants of low molecular weight, such as drug residues, are in the focus of water quality assessment: some of them, like carbamazepine are only partially degraded in wastewater treatment plants. Thus, these pollutants can serve as marker substances for elimination efficiencies. Monitoring water quality demands for selective, high-throughput and multi-target analytical methods. Immunoassays, such as ELISA, offer the possibility to be highly sensitive and selective due to the specific recognition by high affinity of target molecules to antibodies (Abs). Batch-wise processing in microtiter plates allows for the necessary high-throughput, however only a single analyte can be determined within one measurement. To overcome these disadvantages, we developed a four-plex microbead-based flow cytometric assay, which is adaptable for the microtiter plate format. The modular and self-prepared bead support consists of polystyrene-core/silica-shell particles. While, the polystyrene core is used for encoding, by introducing different amounts of fluorescent dyes, the silica shell creates a solid support for the immunoassay: The target analytes, three drugs, carbamazepine, diclofenac and caffeine and the fecal marker isolithocholic acid are coupled covalently to the surface via NHS chemistry to amino groups on the surface. For determination of the pollutants, a mixture of specific Abs is incubated with the samples, to bind competitively on the “anchor” molecules on the surface of the beads or the analyte in solution. Bound antibodies are then visualized via fluorescent dye-labelled secondary Abs. Flow-cytometry allows for decoding of the beads and signal read-out, without washing the system. In order to decrease non-specific binding, we investigated different types of surface modifications, finding, that a PEG-based surface is suitable to support our immunoassay format. For maximum sensitivity, a design-of-experiment approach was chosen for optimization of the assay parameters. The resulting immunoassay is appropriate to quantify the pollutants in the low μg/L-range. T2 - EBS 2017 CY - Potsdam, Germany DA - 20.03.2017 KW - Immunoassay KW - Bead-based assay KW - Flow-cytometry PY - 2017 AN - OPUS4-39522 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider, Rudolf A1 - Hoffmann, Holger A1 - Panne, Ulrich T1 - LC-ELISA as a contribution to the validation of immunoassays N2 - Coupling ELISA and liquid chromatography yields a powerful too to detect cross-reacting substances, interfering matrix compounds and thus to validation of binding assays. T2 - CCQM Workshop: "Advances in Metrology in Chemistry and Biology" CY - Paris, France DA - 08.04.2019 KW - ELISA KW - Immunoassay KW - Validierung PY - 2019 AN - OPUS4-48322 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider, Rudolf A1 - Ecke, Alexander A1 - Bell, Jérémy T1 - Electrochemical immunosensing with a 3-dimensional microfluidic flow cell N2 - Immunoassays, based on analyte recognition and capture by highly selective antibodies with high affinity, are intensively used in all fields of laboratory diagnostics and in screen-ings of food and environmental samples. Yet, for many purposes, online sensors are desir-able, and, in principle, all immunoassay tech-niques can be integrated into lab-on-chip set-ups that can work as continuous monitoring devices. Yet, the challenge remains to devel-op platforms and elements that are fit for a quick transition of laboratory microplate as-says to immunosensors. T2 - European Biosensor Symposium CY - Aachen, Germany DA - 28.08.2023 KW - Biosensor KW - Antibodies KW - Microfluidics KW - Electrochemical detection PY - 2023 AN - OPUS4-59240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider, Rudolf A1 - Riedel, Soraya A1 - Bayram, Rabia A1 - Döring, Sarah A1 - Konthur, Zoltán T1 - Expression of Aspergillus niger Fumonisin Amine Oxidase (AnFAO) for an Electrochemical Detection of the Mycotoxin N2 - The poster describes how molecular biology, especially recombinant expression of proteins, in this case, an enzyme, can underpin developments of biosensors. The fumonisin oxidase produced by the fungus Aspergillus niger (AnFAO) is highly selective for the toxic mycotoxin fumonisin. Its structure and sequence has been published before. We took this information and expressed the enzyme in E. coli. The enzyme proved active and could be employed in an amperometric biosensor for the detection of the mycotoxin. T2 - 30. Leibniz Conference of Advanced Science CY - Berlin, Germany DA - 06.10.2023 KW - Biosensor KW - Enyzme KW - Recombinant KW - Electrochemical detection PY - 2023 AN - OPUS4-59241 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -