Development of a colorimetric assay for the detection of SARS-CoV-2 3CLpro activity.

Diagnostic testing continues to be an integral component of the strategy to contain the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) global pandemic, the causative agent of Coronavirus Disease 2019 (COVID-19). The SARS-CoV-2 genome encodes the 3C-like protease (3CLpro) which is essential for coronavirus replication. This study adapts an in vitro colorimetric gold nanoparticle (AuNP) based protease assay to specifically detect the activity of SARS-CoV-2 3CLpro as a purified recombinant protein and as a cellular protein exogenously expressed in HEK293T human cells.