Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

The development of point-of-care (POC) testing platforms has increased during the COVID-19 pandemic due to their multiple benefits including low cost, rapid turnaround time, on-site testing, and minimal sample preparation [1-2]. Although POC tests are a good alternative to the gold standard technique (reverse-transcriptase-polymerase chain reaction, RT-PCR) for SARS-CoV-2 detection, there are challenges regarding their sensitivity and specificity that need to be addressed [3-4]. One strategy to improve the performance of POC is the integration of nanostructures as sensing elements [5]. In this work, we used interdigitated gold nanowires (Au NWs) in combination with electrical impedance spectroscopy (EIS) for the detection of the receptor-binding domain of the S1 protein of the SARS-CoV-2 virus and the respective antibodies that appear during and after infection. Our sensor system was composed of six sensing devices, each of these sensors containing six pairs of interdigitated gold nanowires of 120 nm in width. The surface of the Au NWs was functionalized with antigens or antibodies of SARS-CoV-2 so that the molecules of interest present in the sample can bind to them. The adhesion of molecules to the surface of the Au NWs modulates the physicochemical properties of the surface [6]. As a result, it was possible to correlate the changes in electrical impedance with the binding of specific analytes to the surface of the Au NWs using EIS. The developed sensing platform is an attractive system for screening during pandemics and can be adapted for the detection of relevant target-analyte pairs in different diseases.

References
[1] E. Valera et al., ?COVID-19 Point-of-Care Diagnostics: Present and Future,? ACS Nano, vol. 15, no. 5, pp. 7899?7906, 2021, doi: 10.1021/acsnano.1c02981.
[2] E. Morales-Narváez and C. Dincer, ?The impact of biosensing in a pandemic outbreak: COVID-19,? Biosens. Bioelectron., vol. 163, p. 112274, 2020, doi: https://doi.org/10.1016/j.bios.2020.112274.
[3] W. Leber, O. Lammel, A. Siebenhofer, M. Redlberger-Fritz, J. Panovska-Griffiths, and T. Czypionka, ?Comparing the diagnostic accuracy of point-of-care lateral flow antigen testing for SARS-CoV-2 with RT-PCR in primary care (REAP-2),? EClinicalMedicine, vol. 38, p. 101011, 2021, doi: 10.1016/j.eclinm.2021.101011.
[4] I. Wagenhäuser et al., ?Clinical performance evaluation of SARS-CoV-2 rapid antigen testing in point of care usage in comparison to RT-qPCR,? EBioMedicine, vol. 69, pp. 1?7, 2021, doi: 10.1016/j.ebiom.2021.103455.
[5] N. Wongkaew, M. Simsek, C. Griesche, and A. J. Baeumner, ?Functional Nanomaterials and Nanostructures Enhancing Electrochemical Biosensors and Lab-on-a-Chip Performances: Recent Progress, Applications, and Future Perspective,? Chem. Rev., vol. 119, no. 1, pp. 120?194, 2019, doi: 10.1021/acs.chemrev.8b00172.
[6] J. L. Hammond, N. Formisano, P. Estrela, S. Carrara, and J. Tkac, ?Electrochemical biosensors and nanobiosensors,? Essays Biochem., vol. 60, no. 1, pp. 69?80, 2016, doi: 10.1042/EBC20150008.