Direct virus capture assay for label-free detection of SARS-CoV-2 virions using laser microscopy

Abstract

Aim: To evaluate a label-free and variant-independent assay called direct virus capture (DVC) for detection of intact SARS-CoV-2 virions through light scattering, utilizing an optical inverted laser microscope called nano eye device virus detector (NED-VD). Methods: The DVC assay involves the interaction between ACE2 receptors printed on a glass coverslip substrate, and the S protein on the outer surface of virions. The study was conducted using 191 human swab specimens. Results: In comparison to the RT-PCR assay, the DVC method achieved a sensitivity of 40.5%, specificity of 90.4% and accuracy of 46%. Conclusion: The study presents a promising qualitative pre-screening test to evaluate the presence of whole virions and reduce the number of PCR tests.