Single-Chained Fragment Variable (scFv) Recombinant as a Potential Receptor for SARS-CoV-2 Biosensor Based on Surface Plasmon Resonance (SPR)

Detection of SASR-CoV-2 plays a significant role in reducing the transmission of COVID-19. Antigen swab test is widely used for screening due to its low processing time and cost, while RT-PCR is used in patient monitoring since it is quite expensive. Although the antigen swab test is more affordable than the RT-PCR, it only generates a discrete result: positive or negative. Thus, it cannot be used for patient monitoring. A method using antigen-antibody binding and surface plasmon resonance (SPR) principle was developed in this research to create an affordable, instant, and quantified SARS-CoV-2 detection method. In this study, modified scFv is tested as a potential bioreceptor since it is easier to be expressed than the whole antibody. The results show that the scFv with the best potential was harvested from the periplasm of E. coli and purified. It has a maximum response at 8.02 RU, LOD at 8.34 ng/mL, linearity at 1.38 in the range of 25-200 ng/mL, and a determination coefficient at 92 percent.