TY - JOUR A1 - Carl, Peter A1 - Sarma, Dominik A1 - Gregório, Bruno J. R. A1 - Hoffmann, Kristin A1 - Lehmann, Andreas A1 - Rurack, Knut A1 - Schneider, Rudolf T1 - Wash-Free Multiplexed Mix-and-Read Suspension Array Fluorescence Immunoassay for Anthropogenic Markers in Wastewater N2 - Pharmaceuticals, certain food ingredients, and mammalian endogenous metabolic products in wastewater are mostly of human origin. They are anthropogenic markers. Proper knowledge of their levels in wastewater helps to track sources of pollutants in natural waters and allows for calculation of removal efficiencies in wastewater Treatment plants. Here, we describe the development and application of an indirect competitive, multiplexing suspension Array fluorescence immunoassay (SAFIA) for the detection of carbamazepine (CBZ), diclofenac (DCF), caffeine (CAF), and isolithocholic acid (ILA) in wastewater, covering those classes of anthropogenic markers. The assay consists of haptens covalently conjugated to fluorescence-encoded polystyrene core/silica shell microparticles to create a site for competitive binding of the antibodies (Abs). Bound Abs are then stained with fluorophore-labeled Abs. Encoding and signaling fluorescence of the particles are determined by an automated flow cytometer. For compatibility of the immunoassay with the 96-well microtiter plate format, a stop reagent, containing formaldehyde, is used. This enables a wash-free procedure while decreasing time-to-result. Detection limits of 140 ± 40 ng/L for CBZ, 180 ± 110 ng/L for CAF, 4 ± 3 ng/L for DCF, and 310 ± 70 ng/L for ILA are achieved, which meet the sensitivity criteria of wastewater analysis. We demonstrate the applicability of SAFIA to real wastewater samples from three different wastewater Treatment plants, finding the results in good agreement with LC-MS/MS. Moreover, the accuracy in general exceeded that from classical ELISAs. We therefore propose SAFIA as a quick and reliable approach for wastewater analysis meeting the requirements for process analytical technology. KW - Suspension Array KW - Immunoassay KW - Carbamazepine KW - Caffeine KW - Diclofenac KW - SAFIA PY - 2019 DO - https://doi.org/10.1021/acs.analchem.9b03040 SN - 0003-2700 VL - 91 IS - 20 SP - 12988 EP - 12966 PB - ACS Publications AN - OPUS4-49305 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 - Carvalho, José Joao A1 - Walter, Astrid A1 - Baermann, Yvonne A1 - Weller, Michael G. A1 - Panne, Ulrich A1 - Schenk, J.A. A1 - Schneider, Rudolf T1 - Non-invasive monitoring of immunization progress in mice via IgG from feces N2 - A non-invasive method to monitor the humoral immune response in mice after immunization is described. From fecal pellets of an individual mouse, a sufficient amount of active immunoglobulins or their fragments can be extracted to perform a regular examination of the status of the immune response by immunoassay. Hapten-specific antibodies from the feces of mice from three immunization trials showed very similar characteristics to those obtained from serum at a given date. Therefore, it can be suspected that some serum IgG enters the intestinal lumen and ends up in the feces, where they appear to be considerably stable. Hapten-specific IgAs were not found in the feces. Being able to analyze antibody titers in feces could be an interesting animal welfare refinement to standard practice that does not entail repeated blood sampling. KW - Immunization monitoring KW - IgG KW - Coproantibodies KW - Feces KW - Animal welfare KW - 3R concept PY - 2012 UR - http://iv.iiarjournals.org/content/26/1/63.full.pdf+html SN - 0258-851x VL - 26 IS - 1 SP - 63 EP - 70 PB - In vivo CY - Athens AN - OPUS4-25283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Devi, Sarita A1 - Goel, S. A1 - Rani, S. A1 - Schneider, Rudolf J. A1 - Rohilla, R. A1 - Kumari, Surbhi A1 - Prabhakar, N. T1 - MOF-metal nanohybrid-assisted charge transfer amplification for electrochemical biosensing of the MUC1 cancer biomarker N2 - Cancer is a severe disease characterized by high mortality and complex pathophysiology; however, its early and accurate diagnosis remains inadequate. Conventional diagnostic approaches often fall short, particularly for dense tissues, and are frequently invasive, costly, and of limited availability. This reinforces the need for a compact, economical, and ultrasensitive assay that is operationally simple and interpretable. We present an efficient electrochemical detection platform for the cancer biomarker mucin 1 (MUC1). A fluorine-doped tin oxide (FTO) surface was modified with an iron-based metal–organic framework (FeMOF) intercalated with palladium nanorods (PdNR). FeMOF was prepared using Fe3+/Fe2+ precursors at a 1.2/1 mmol ratio and dual ligands, i.e. tetrahydroxy-1,4-benzoquinone and 2-aminobenzene-1,4-dicarboxylic acid. AntiMUC1 antibodies were immobilized on a modified electrode via p-phenylenediamine (PDA) (FTO/FeMOF@PdNR/PDA/antiMUC1Ab) and evaluated using electrochemical impedance spectroscopy (EIS) and voltammetry. The designed sensor demonstrated an excellent binding affinity for the MUC1 antigen. Among these techniques, the EIS method stands out for its technical performance, as evidenced by the high sensitivity (detection limit 0.074 fg mL−1), quantification limit 0.24 fg mL−1, and high analytical sensitivity (1.39 × 103 Ω fg−1 mL−1 cm−2). The negligible cross-reactivity with interferent biomolecules, rapid response (10-minute equilibrium), regenerability up to 5 cycles, high reproducibility (RSD ∼1–3%), and long-term stability (up to 35 days) further validate the suitability of the proposed MUC1 immunosensor. This study presents an ultrasensitive biosensor that is compact, cost-effective, and easy for individuals at home to use after further development into a kit-based end product. Moreover, its excellent functionality for spiked serum samples shows promise for next-generation clinical diagnostics. KW - Antibodies KW - Metal-organic framework KW - Immunoassay PY - 2026 DO - https://doi.org/10.1039/D6AN00018E SP - 1 EP - 11 PB - Royal Society of Chemistry CY - London AN - OPUS4-65726 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -