Validation of Smart Masks for Surveillance of COVID-19

Vulnerable populations do not just need testing; they need surveillance. The ideal surveillance tool would operate in the background with minimal involvement of the population to be tested; it would be simple, affordable, reliable, and accurate. Unfortunately, no such assay existed. This project examined a smart mask that changes colors when the wearer has been exposed to biomarkers (proteases) of COVID-19 -- a novel approach to surveillance because most people are already wearing masks, especially in high-risk settings. The first goal was to optimize the reagents that will test the proteases. The peptide sequences were customized such that the reagents change color only when two key SARS proteases were present. After characterizing the colorimetric reagents, Aim 2 integrated these reagents into an adhesive test strip that can be affixed to any existing cloth or surgical mask. Aim 3 involved validation with human subjects. First, biobanked saliva samples that were confirmed to be either COVID-19-positive or COVID-19-negative were used. Next, how long people infected with SARS-CoV-2 must breathe through the smart mask before it changed color was evaluated. Finally, the smart mask was used for surveillance of a population that was concurrently being tested regularly via PCR. The sensitivity and specificity of the smart masks were calculated through comparison to PCR. True positives, true negatives, false positives, and false negatives were measured and 800 subjects were recruited at the University of California, San Diego.