Development of a handheld rapid air sensing system to monitor and quantify SARS-CoV-2 in aerosols in real-time

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Project Summary The ability to rapidly monitor SARS-CoV-2 in aerosol—drop particles <5 μm in size that evaporate into droplet nuclei and become suspended in air—at the point of presentation is critical to managing the risk of infection by airborne transmission as people return to their communities, workplaces, and schools during the COVID-19 pandemic. However, current enzyme-based methods lack sensitivity, speed, simplicity, and require lab equipment—hence, lack the capability for real-time point-of-presentation (POP) monitoring. In the absence of a real-time POP monitoring capability, SARS-CoV-2 transmission remains poorly understood. In this application, a multidisciplinary research approach that integrates innovations in rapid-kinetic chemical auto-ligation, non- enzymatic isothermal signal amplification, solid-state electronics, and biophotonics is proposed to enable the development of a novel air monitoring system (AMS) that detects and quantifies aerosolized SARS-CoV-2 at the point of presentation in real-time. Recent advances in viral culturing protocols, air sampling technology, and single-photon detection capability will provide the framework for a collaborative research endeavor to establish a new paradigm to address the knowledge gap between the spread of COVID-19 and SARS-CoV-2 aerosol transmission. Therefore, the proposal is aimed at transforming the way COVID-19 is currently researched by providing a tool to enable unparalleled studies that will significantly advance the current knowledgebase. These transformative studies could ultimately guide a new field of investigations that lead to a better understanding of COVID-19 spread, such as viral exposure vs. risk, viral decay rate vs. infectivity, and viral load vs. infectious dose in SARS-CoV-2 airborne transmission. At a minimum, the proposed three research objectives will provide a basic understanding of COVID-19 aerosol transmission. Firstly, current air sampling systems use a multi-step workflow that takes several hours to complete and requires lab equipment, reagents, and significant hands-on time. The goal of objective 1 is to combine air sampling and detection into a one-step real-time POP AMS device that yields SARS-CoV-2 quantification results in less than 5 minutes, without lab equipment or reagents. Secondly, viral inoculum, or initial dose of virus, aspirated into the nasal cavity and lungs has been associated with disease onset and severity. The goal of objective 2 is to optimize and validate AMS to correlate readings from the air monitoring device with tissue-culture infectious dose (TCID50) and reverse transcription polymerase chain reaction (RT-PCR) quantities. These parameters can then later be applied to Human studies to determine the Human infectious dose of SARS-CoV-2 by aerosol transmission. Thirdly, field-based testing in hospitals will provide a means to beta test AMS performance in high-risk environments. The goal of objective 3 is to calibrate AMS measurements with RT-PCR cycle-threshold (Ct) values and cell-culture TCID50 viability results and then benchmark with results from high-risk environments taken from around the world to correlate SARS-CoV-2 aerosol concentrations with global infection rate, as a potential for establishing threshold levels.