TY - CONF A1 - Ramos, I. I. A1 - Carl, Peter A1 - Schneider, Rudolf A1 - Segundo, M. A. T1 - Automated bead-based immunoassay for the determination of carbamazepine in wastewater N2 - The improvement of immunoanalytical methods for the determination of pharmaceuticals in wastewaters is a crucial yet challenging endeavor. In this work, the development of an automated miniaturized ELISA based on micro-Bead Injection Spectroscopy (μ-BIS) [1] for the determination of carbamazepine, a widely employed anti-epileptic drug and emergent pollutant [2], was pursued. The experimental workflow comprised the offline functionalization of Sepharose beads with specific anti-CBZ antibodies via affinity immobilization using protein G, and 3 online steps inside the microfluidic analyzer lab-on-valve (LOV): I) packing of the bead column into the detection unit; II) sequential percolation of sample and a CBZ competitor- labeled with horseradish peroxidase (tracer) through the bead column; and III) on-column colorimetric detection employing the enzyme substrate 3,3’,5,5’-tetramethylbenzidine. After each analysis, the bead column was discarded, and the flow cell was washed before receiving new beads. The elimination of manual washing steps is a novel feature compared to batch-wise ELISA, making the method less error-prone and therefore more robust. The replacement of the solid support prevents memory effects and cross-contamination between runs. The use of microparticles as solid support for the molecular recognition elements accounts for high area-to-volume ratios, and low molecular diffusion distances. For that reason, time-to-result was reduced from several hours to less than 10 min. The consumption of reagents was also very low. For instance, only ca. 200 μg of solid support and 900 ng of anti-CBZ antibody were required per determination. At last, the versatility of the LOV platform offers the possibility of adapting the assay to other relevant pharmaceuticals and anthropogenic markers in water. Acknowledgements: Inês I. Ramos thanks FCT (Fundação para a Ciência e a Tecnologia) and POPH (Programa Operacional Potencial Humano) for her grant (SFRH/BD/97540/2013). This work received financial support from the European Union (FEDER funds POCI/01/0145/FEDER/007265) and National Funds (FCT/MEC - Ministério da Educação e Ciência) under the Partnership Agreement PT2020 UID/QUI/50006/2013. Financial support from Deutscher Akademischer Austauschdienst and from Fundação das Universidades Portuguesas under the protocol CRUP-DAAD (Ações Integradas Luso-Alemãs nºE-20/16) is also acknowledged. [1] Gutzman, Y.; Carrol, A. D. Analyst 2006, 131, 809. [2] Murray, K. E.; Thomas, S. M.; Bodour, A. A. Environ. Pollut. 2010, 158, 3462. T2 - ANALÍTICA – 2018 CY - Porto, Portugal DA - 26.03.2018 KW - Lab-on-valve KW - Emerging pollutants KW - Immunoassay KW - Automation PY - 2018 AN - OPUS4-44592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 JF - Analytica Chimica Acta 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 - CONF A1 - Ramos, I. I. A1 - Carl, Peter A1 - Barreiros, L. A1 - Magalhães, L. M. A1 - Reis, S. A1 - Schneider, Rudolf A1 - Segundo, M. A. T1 - Lab-on-valve platform for real-time automated immunosensing N2 - The talk presents results of collaborative work on implementing antibody-based, immunoanalytical methods on a lab-on-valve platform. T2 - Biosensors 2018 CY - Miami, FL, USA DA - 12.07.2018 KW - Antikörper KW - Immunoassay KW - Automation PY - 2018 AN - OPUS4-47049 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ramos, Inês I. A1 - Carl, Peter A1 - Schneider, Rudolf A1 - Segundo, Marcela A. A1 - Barreiros, Luisa A1 - Magalhaes, Luís M. A1 - Reis, Salette T1 - Development of automated immunosensing methods for clinical and environmental Analysis using lab-on-valve platforms N2 - The lab-on-valve (LOV) is a mesofluidic platform that has been recently exploited for the automation and miniaturization of bioanalytical assays, resorting namely to molecular recognition schemes based on immunosensing. Due to its high versatility for reagent accommodation, it is possible to establish immunoassays under several formats (eg. direct competitive ELISA, sandwich ELISA or even label-free immunoaffinity chromatography). For instance, the LOV has been used as a manifold for UV-vis micro-Bead Injection Spectroscopy (μ-BIS), a technique that involves the quantification of the target analyte by direct measurement on the surface of a solid phase capable of retaining the target analyte by molecular recognition. The μ-BIS-LOV strategy affords several analytical advantages, namely short time-toresult intervals (3 to 15 min), low sample volume (1-20 μL), automated solution handling and washing steps, downscaling of reagents’ consumption, low-cost analysis and little generation of waste. Additionally, the solid support is renewed before each determination, minimizing surface fouling, cross-contamination issues and functional group deactivation. No sample clean-up steps are required because interferences are separated from the target analyte upon quantification mediated by a molecular recognition element attached to the micro-bead column. The portability of the LOV device makes it compatible with point-of-care testing. To our knowledge, this technique has been mainly employed for the evaluation and optimization of bioaffinity processes, but its potential for clinical and environmental analysis remains underexploited. Hence, in this communication, different immunosensing strategies using the LOV platform will be addressed, namely the determination of autoimmune IgG in human serum, and the assessment of drug (carbamazepine) levels in wastewater samples. T2 - EBS 2017 CY - Potsdam, Germany DA - 20.03.2017 KW - Lab-on-valve KW - Automation KW - Immunoassay PY - 2017 AN - OPUS4-39521 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Carl, Peter A1 - Ramos, Inês I. A1 - Segundo, Marcela A. A1 - Schneider, Rudolf T1 - Antibody conjugation to carboxyl-modified microspheres through N-hydroxysuccinimide chemistry for automated immunoassay applications: A general procedure JF - PLoS ONE N2 - Immunochemical techniques are the workhorse for sample enrichment and detection of a large variety of analytes. In contrast to classical microtiter plate-based assays, microparticles are a next generation solid support, as they promote automation of immunoassays using flow-based techniques. Antibody immobilization is a crucial step, as these reagentsmare expensive, and inefficient coupling can result in low sensitivities. This paper proposes a general procedure for efficient immobilization of antibodies onto TentaGel particles, via Nhydroxysuccinimide chemistry. The goal was the preparation of solid supports with optimum immunorecognition, while increasing the sustainability of the process. The influence of buffer composition, activation and coupling time, as well as the amount of antibody on the immobilization efficiency was investigated, resorting to fluorophore-labeled proteins and fluorescence imaging. Buffer pH and activation time are the most important parameters for efficient coupling. It is demonstrated, that the hydrolysis of N-hydroxysuccinimide esters occurs at similar rates as in solution, limiting the utilizable time for coupling. Finally, applicability of the generated material for automated affinity extraction is demonstrated on the mesofluidic platform lab-on-valve. KW - Mesofluidics KW - Bead injections KW - ELISA KW - Carbamazepine KW - Biomarkers PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483919 DO - https://doi.org/10.1371/journal.pone.0218686 SN - 1932-6203 VL - 14 IS - 6 SP - e0218686, 1 EP - 18 PB - Public Library of Science CY - San Francisco, California, USA AN - OPUS4-48391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gregório, Bruno J.R. A1 - Ramos, Inês I. A1 - Marques, Sara S. A1 - Barreiros, Luísa A1 - Magalhães, Luís M. A1 - Schneider, Rudolf A1 - Segundo, Marcela A. T1 - Microcarrier-based fluorescent yeast estrogen screen assay for fast determination of endocrine disrupting compounds JF - Talanta N2 - The presence of endocrine-disrupting compounds (EDCs) in water poses a significant threat to human and animal health, as recognized by regulatory agencies throughout the world. The Yeast Estrogen Screen (YES) assay is an excellent method to evaluate the presence of these compounds in water due to its simplicity and capacity to assess the bioaccessible forms/fractions of these compounds. In the presence of a compound with estrogenic activity, Saccharomyces cerevisiae cells, containing a lacZ reporter gene encoding the enzyme β-galactosidase, are induced, the enzyme is synthesised, and released to the extracellular medium. In this work, a YES-based approach encompassing the use of a lacZ reporter gene modified strain of S. cerevisiae, microcarriers as solid support, and a fluorescent substrate, fluorescein di-β-D-galactopyranoside, is proposed, allowing for the assessment of EDCs’ presence after only 2 h of incubation. The proposed method provided an EC50 of 0.17 ± 0.03 nM and an LLOQ of 0.03 nM, expressed as 17β-estradiol. The assessment of different EDCs provided EC50 values between 0.16 and 1.2 × 103 nM. After application to wastewaters, similar results were obtained for EDCs screening, much faster, compared to the conventional 45 h spectrophotometric procedure using a commercial kit, showing potential for onsite high-throughput screening of environmental contamination. KW - Biosensoren KW - YES assay KW - Endokrine Disruptoren PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602315 DO - https://doi.org/10.1016/j.talanta.2024.125665 VL - 271 SP - 1 EP - 7 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-60231 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -