A SARS-CoV-2 Breathalyzer for Direct Virus Detection

A substantial and growing body of evidence demonstrated that COVID-19 is transmitted by human-emitted airborne particles; therefore, it was critical to rapidly screen individuals to determine whether they are at risk of transmitting the disease to others before they enter large venues (e.g., airports, schools) and smaller ones where extended exposure or close proximity is expected (e.g., dental offices, hair salons). Given the large number of asymptomatic cases of the disease, the infrared thermometers and health questionnaires frequently used to screen individuals are plainly inadequate. Existing SARS-CoV-2 detection technology is time-consuming and complicated to use, expensive and not portable, and therefore ill-suited to use as point-of-care (POC) screening tools. Tests recently approved by the FDA under the Emergency Use Authorization face some of the same challenges. The goal of this project was to develop and test a novel breathalyzer for detecting aerosolized SARS-CoV-2 directly from exhaled breath in near real-time by marrying a proven, cutting-edge aerosol sampling technology with a novel and inexpensive virus detector. The innovation was directly detecting virus in the breath, while other breathalyzers depend on indirect detection (VOCs and AI algorithms) to infer the presence of the virus. In this Fast-track STTR project, Aerosol Devices Inc (ADev) modified its commercial bioaerosol collector, which was used to sample from the ambient environment, to enable it to collect viruses from breath samples into a concentrated liquid sample. The University of Minnesota (UMN) modified its Magnetic Particle Spectrometer (MPS), a version of which has previously been used to detect Influenza A H1N1 virus, so that the liquid samples from the collector could be analyzed to detect SARS-CoV-2. Specific aims included developing the hardware for transforming an ambient sampler into a breath sampler, designing a rapid means of decontaminating the collector between tests, integrating the collector and the detector into a robust package, functionalizing magnetic nanoparticles with SARS-CoV-2 antibodies, increasing the signal/noise ratio of the MPS electronics, reducing the assay time, improving the analytical sensitivity/specificity, measuring the clinical sensitivity/specificity and comparing to RT-qPCR in pre-clinical testing. The technology platform proposed was flexible and extensible and was tailored to detect other pathogens (e.g., rhinoviruses, respiratory syncytial virus, parainfluenza virus, other coronaviruses, etc.). This flexibility was valuable since (1) this will not be the last pandemic (new pathogens in the future) and (2) development could pivot to a different pathogen if a vaccine or other control measures bring the current COVID-19 pandemic under control before this SARS-CoV-2 breathalyzer was made commercially available.