Biosensors in forensic sciences: application for SARS-CoV-2 detection

Identifier:  TFM:606

Handle: https://hdl.handle.net/20.500.11797/TFM606

Authors:  Cid Martinez, Paula

Abstract:
Background: Current methods in forensic analysis are usually time-consuming, require sample pre-treatment procedures and/or have low sensibility. The development of biosensors for biological and chemical determinations in medical diagnostics, environmental monitoring, drug detection and food safety analysis are taking advantage over traditional methods given their greater speed, ease of handling and sensitivity. The coronavirus disease-19 (COVID-19) caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has suddenly emerged as one of the major public health concerns because of its rapid spread and mortality. The actual methodologies for the early detection of the virus are quite slow and imprecise. The main objective of this work is to design a methodology for the detection of nucleic acids from SARS-CoV-2 by using a Surface Plasmon Resonance (SPR) biosensor in order to obtain a faster and more sensitive diagnostic tool. Methods: Two different biofunctionalization methods (chemisorption and covalent attachment) of the SPR biosensor chip, three conditions for probe incubation over the chip surface and five different hybridization buffers were tested for the optimization of the target detection. Additionally, we tested whether the use of lateral spacers during the chip biofunctionalization improves any aspect of the methodology. Results: Chemisorption allowed for a higher target detection compared with covalent attachment methods. Moreover, the incubation of the probe ex-situ and overnight over the chip surface showed a better sensibility when compared when ex-situ for three hours and in-situ overnight. The 5X SSC hybridization buffer showed higher hybridization efficiency than the other buffers tested. Finally, we found that the use of lateral spacers during the biofunctionalization allows for the use of lower target DNA concentrations. Conclusions: The different strategies followed for the optimization of the SARS-CoV-2 deoxyribonucleic acid (DNA) detection point the use of SPR biosensors as a potential new faster, easier and more sensitive diagnostic tool. Keywords: biosensor, SARS-Cov-2, nucleic acids.