COVID-19: High Efficiency SARS-CoV-2 Virus Aerosol Sampling and Sensing

As the current COVID-19 pandemic has demonstrated, aerosolized pathogens such as SARS-CoV-2 can spread explosively if not quickly detected. Early detection of these airborne pathogens can help control out- breaks, particularly within vulnerable populations in densely populated spaces including assisted living facili- ties, places of worship, military installations, hospitals, and prisons. To date, most studies of aerosolized SARS-CoV-2 use filter collection followed by laboratory analysis of viral RNA. While this gives a general indica- tion of viral RNA levels in an environment, filters collect both infectious and non-infectious viruses and damage them through mechanical stress and desiccation, making it difficult to determine the infective fraction of the col- lected viruses. Further, current filter analysis methods require time-consuming nucleic acid extraction and am- plification techniques not suitable to rapid, point-of-care monitoring. Therefore, there is an urgent need for in- struments that can detect intact viruses at the point-of-care. We propose to develop a sensitive, direct reading, bioaerosol detection platform that can quantify specific air- borne pathogens at the point of collection. Furthermore, if a positive result is identified, the sample can be taken to a central laboratory for additional molecular analysis and infectivity testing. This device will integrate the bioaerosol collection technology developed at Aerosol Devices Inc. (ADev) with virus detection technology from Colorado State University (CSU). Using gentle condensation-growth capture that mimics the human lung, the ADev sampler will be the front-end of the platform, concentrating intact, viable virus particles into a small liquid volume. With andgt;90% collection efficiency for particle sizes andlt;10 nm up to 10 µm, ADev samplers uniformly collect all inhalable SARS-CoV-2 particles whether originating from cough droplets (andgt;5 µm), smaller particles exhaled during breathing or talking (andlt;5 µm), or shed as individual virus particles (~120 nm). CSU Professors Henry, Dandy, and Geiss are developing innovative, inexpensive electrochemical biosensors to rapidly detect intact viruses in liquid samples. By synergizing these robust sensors with the ADev aerosol sampler, we will produce a system that can detect and quantify ultra-low concentrations of viral pathogens in near real-time. In this phase I STTR project, we will adapt our commercial aerosol-into-liquid collector to incorporate CSU’s biosensors. Specific aims for the ADev sampler include extending sampling time to 24 h to enhance limits of detection, increasing volumetric sampling rate to improve temporal resolution, selecting materials compatible with VHP decontamination and optimizing the system to reduce size, weight, power consumption and cost. Specific aims for the biosensor include modifying electrodes to detect SARS-CoV-2 particles with high sensitiv- ity and selectivity, adapting our current electrode configuration to work with the ADev sampling vial, and testing the system with infectious SARS-CoV-2 in our BSL-3 laboratory. Our immediate focus is SARS-CoV-2, but this technology can be adapted in Phase II to detect any airborne pathogen (e.g., Influenza, B. anthracis, etc.).Project Narrative Transmission of SARS-CoV-2 as aerosol is a major contributor to the rapid spread of COVID-19. There is an urgent need for tools that provide early warning of respiratory exposure to airborne virus particles for vulnerable populations at the point-of-care (e.g., nursing homes, airports, prisons or public transportation) to facilitate timely intervention and limit the spread of the disease. In this project, we will synergize our robust commercial ADev condensation growth sampler with CSU’s unique virus detection technology to develop an aerosol sampling system that collects and concentrates intact virus particles for near-real-time detection with an integrated ultra-sensitive electrochemical biosensor.