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Using Soft Aerosolization and Sampling Techniques for the Conservation of Virus Infectivity during Airborne Exposure Experiments
GHISLAIN MOTOS, Kalliopi Violaki, Aline Schaub, Shannon David, Tamar Kohn, Athanasios Nenes, EPFL, LAPI, Lausanne
Abstract Number: 229
Working Group: Instrumentation and Methods
Abstract
Recurrent epidemic outbreaks such as the seasonal flu and the ongoing COVID-19 are disastrous events to our societies both in terms of fatalities, social and educational structures, and financial losses.
Further scientific research thus needs to be conducted to better understand the mechanistic processes that lead to airborne virus inactivation as well as the environmental conditions favourable to these processes. In addition to modelling and epidemiological studies, chamber experiments offer to simulate everyday life conditions for virus transmission. However, the current standard instrumental solutions for virus aerosolization to the chamber and sampling from it use high fluid forces and recirculation which can be highly damaging to the biological material (Alsved et al., 2020) and also do not represent the most relevant production of airborne aerosol in the respiratory tract.
In this study, we utilized two of the softest aerosolization and sampling techniques: the sparging liquid aerosol generator (SLAG, CH Technologies Inc., Westwood, NJ, USA), which forms aerosol from a liquid suspension by bubble bursting, thus mimicking natural aerosol formation in wet environments (e.g. the respiratory system but also lakes, sea, toilets, etc…); and the viable virus aerosol sampler (BioSpot-VIVAS, Aerosol Devices Inc., Fort Collins, CO, USA), which uses condensational growth to gently collect particles down to a few nanometres in size. We characterize these systems with particle sizers and biological analysers using non-pathogenic viruses such as phages suspended in surrogate lung fluid and artificial saliva. We compare the size distribution of produced aerosol from these suspensions against similar distributions generated with standard nebulizers, and assess the ability of these devices to produce aerosol that much more resembles that produced in human exhaled air. We also assess the conservation of viral infectivity with the VIVAS vs. conventional biosamplers.