TY - JOUR A1 - Martínez, N.A. A1 - Schneider, Rudolf A1 - Messina, G.A. A1 - Raba, J. T1 - Modified paramagnetic beads in a microfluidic system for the determination of ethinylestradiol (EE2) in river water samples N2 - In this work, we have developed and characterized a novel microfluidic immunoassay methodology for rapid and sensitive quantification of ethinylestradiol (EE2) in river water samples. The detection of EE2 was carried out using a competitive direct immunoassay method based on the use of anti-EE2 polyclonal antibodies immobilized on magnetic microspheres 3-aminopropyl-modified manipulated for an external removable magnet. The EE2 present in the water sample was allowed to compete with EE2-horseradish peroxidase (HPR) conjugated for the immobilized anti-EE2 antibody. The HPR, in the presence of hydrogen peroxide (H2O2) catalyzes the oxidation of catechol (Q) whose back electrochemical reduction was detected on gold electrode at 0.0 V. The response current obtained from the product of enzymatic reaction is inversely proportional to the amount of EE2 in the water sample. The electrochemical detection can be done within 1 min and total assay time was 30 min. The calculated detection limits for electrochemical detection and the ELISA procedure are 0.09 and 0.32 ng L-1 respectively and the intra- and inter-assay coefficients of variation were below 5.8%. Our electrochemical immunosensor showed higher sensitivity and lower time consumed than the standard spectrophotometric detection ELISA method, which shows the potential for assessment of EE2 in river water samples. KW - Enzyme immunoassays KW - Ethinylestradiol KW - Paramagnetic beads KW - Horseradish peroxidase KW - Microfluidic KW - Flow injection analysis PY - 2010 DO - https://doi.org/10.1016/j.bios.2009.10.031 SN - 0956-5663 SN - 1873-4235 VL - 25 IS - 6 SP - 1376 EP - 1381 PB - Elsevier CY - Barking, Essex, UK AN - OPUS4-22188 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martínez, N.A. A1 - Pereira, S.V. A1 - Bertolino, F.A. A1 - Schneider, Rudolf A1 - Messina, G.A. A1 - Raba, J. T1 - Electrochemical detection of a powerful estrogenic endocrine disruptor: ethylestradiol in water samples through bioseparation procedure N2 - The synthetic estrogen ethinylestradiol (EE2) is an active component of oral contraceptives (OCs), considered as an endocrine disrupting compound (EDC). It is excreted from humans and released via sewage treatment plant effluents into aquatic environments. EDCs are any environmental pollutant chemical that, once incorporated into an organism, affects the hormonal balance of various species including humans. Its presence in the environment is becoming of great importance in water quality. This paper describes the development of an accurate, sensitive and selective method for capture, preconcentration and determination of EE2 present in water samples using: magnetic particles (MPs) as bioaffinity support for the capture and preconcentration of EE2 and a glassy carbon electrode modified with multi-walled carbon nanotubes (MWCNTs/GCE) as detection system. The capture procedure was based on the principle of immunoaffinity, the EE2 being extracted from the sample using the anti-EE2 antibodies (anti-EE2 Ab) which were previously immobilized on MPs. Subsequently the analyte desorption was done employing a sulfuric acid solution and the determination of the EE2 in the pre-concentrated solution was carried out by square wave voltammetry (SWV). This method can be used to determine EE2 in the range of 0.035–70 ng L-1 with a detection limit (LOD) of 0.01 ng L-1 and R.S.D. < 4.20%. The proposed method has been successfully applied to the determination of EE2 in water samples and it has promising analytical applications for the direct determination of EE2 at trace levels. KW - Magnetic particles KW - Bioseparation KW - Ethinylestradiol KW - Electrochemistry KW - Immunoassay KW - Elektrochemischer Sensor KW - Endokrine Disruptoren KW - Hormone KW - EE2 KW - Östrogene PY - 2012 DO - https://doi.org/10.1016/j.aca.2012.02.033 SN - 0003-2670 SN - 1873-4324 SN - 0378-4304 VL - 723 SP - 27 EP - 32 PB - Elsevier CY - Amsterdam AN - OPUS4-25656 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider, Rudolf J. T1 - Evaluating the Normalization Potential of Anthropogenic Markers in Wastewater: Monitoring Influents of German Treatment Plants by ELISA N2 - Wastewater-based epidemiology (WBE) has emerged as a vital tool for pandemic preparedness, offering early warning capabilities and supporting public health interventions. In Germany, combined sewer systems are prevalent, leading to fluctuations in wastewater volume and com-position due to rainwater inflow, especially through street drains. This variability complicates the quantitative measurement of pathogens and pollutants in wastewater. While human excretion provides constant inputs, these parameters are often non-specific, lost, or degraded during transport. Pharmaceuticals—such as carbamazepine, diclofenac, and clarithromycin—as well as commonly consumed substances like caffeine, exhibit sufficiently high concentrations and good chemical stability in wastewater and are not subject to seasonal fluctuations. Antibody-based methods, particularly Enzyme-Linked Immunosorbent Assays (ELISA), offer a cost-effective alternative to complex chromatographic techniques for monitoring anthropogenic markers. They demonstrate superior normalization quality compared to the frequently used quantitative PCR-based marker Pepper mild mottle virus (PMMoV). T2 - 6th International Conference on Risk Assessment of Pharmaceuticals in the Environment - ICRAPHE CY - Aveiro, Portugal DA - 20.10.2025 KW - Carbamazepin KW - Koffein KW - Spurenstoffe KW - Anthropogener Marker Immunoassay PY - 2025 AN - OPUS4-64432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Riedel, Soraya A1 - Hülagü, Deniz A1 - Bennet, Francesca A1 - Carl, Peter A1 - Flemig, Sabine A1 - Schmid, Thomas A1 - Schenk, J. A. A1 - Hodoroaba, Vasile-Dan A1 - Schneider, Rudolf T1 - Electrochemical Immunomagnetic Ochratoxin A Sensing: Steps Forward in the Application of 3,3’,5,5’- Tetramethylbenzidine in Amperometric Assays N2 - Electrochemical methods offer great promise in meeting the demand for user-friendly on-site devices for Monitoring important parameters. The food industry often runs own lab procedures, for example, for mycotoxin analysis, but it is a major goal to simplify analysis, linking analytical methods with smart technologies. Enzyme-linked immunosorbent assays, with photometric detection of 3,3’,5,5’-tetramethylbenzidine (TMB),form a good basis for sensitive detection. To provide a straightforward approach for the miniaturization of the detectionstep, we have studied the pitfalls of the electrochemical TMB detection. By cyclic voltammetry it was found that the TMB electrochemistry is strongly dependent on the pH and the electrode material. A stable electrode response to TMB could be achieved at pH 1 on gold electrodes. We created a smartphonebased, electrochemical, immunomagnetic assay for the detection of ochratoxin A in real samples, providing a solid basis forsensing of further analytes. KW - Ochratoxin A KW - Amperometry KW - Cyclic voltammetry KW - Electrochemistry KW - Immunoassay PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530421 DO - https://doi.org/10.1002/celc.202100446 N1 - Geburtsname von Riedel, Soraya: Höfs, S. - Birth name of Riedel, Soraya: Höfs, S. VL - 8 IS - 13 SP - 2597 EP - 2606 AN - OPUS4-53042 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 -