Rapid Direct Detection of SARS-CoV-2 Aerosols in Exhaled Breath at the Point of Care

Airborne transmission via virus-laden aerosols is a dominantroutefor the transmission of respiratory diseases, including severe acuterespiratory syndrome coronavirus 2 (SARS-CoV-2). Direct, non-invasivescreening of respiratory virus aerosols in patients has been a long-standingtechnical challenge. Here, we introduce a point-of-care testing platformthat directly detects SARS-CoV-2 aerosols in as little as two exhaledbreaths of patients and provides results in under 60 s. It integratesa hand-held breath aerosol collector and a llama-derived, SARS-CoV-2spike-protein specific nanobody bound to an ultrasensitive micro-immunoelectrodebiosensor, which detects the oxidation of tyrosine amino acids presentin SARS-CoV-2 viral particles. Laboratory and clinical trial resultswere within 20% of those obtained using standard testing methods.Importantly, the electrochemical biosensor directly detects the virusitself, as opposed to a surrogate or signature of the virus, and issensitive to as little as 10 viral particles in a sample. Our platformholds the potential to be adapted for multiplexed detection of differentrespiratory viruses. It provides a rapid and non-invasive alternativeto conventional viral diagnostics.