Physicochemical study of coronavirus surrgogate TGEV

Effective airborne transmission of coronaviruses via liquid microdroplets requires a virion structure that must withstand harsh environmental conditions [1]. Due to the demanding biosafety requirements for study of human respiratory viruses, it is important to develop surrogate models to facilitate their investigation. Here we explore the mechanical properties and nanostructure of transmissible gastroenteritis virus (TGEV) virions, an alphacoronavirus, in liquid milieu and their response to different chemical agents commonly used as biocides[2]. Our AFM experiments provide two-fold results on virus stability: First, while particles with larger size and lower packing fraction kept their morphology intact after successive mechanical aggressions, smaller viruses with higher packing fraction showed conspicuous evidence of structural damage and content release. Second, monitoring the structure of single TGEV particles in the presence of detergent and alcohol in real time revealed the stages of gradual degradation of virus structure in situ. These data suggest that detergent is three orders of magnitude more efficient than alcohol in destabilizing TGEV virus particles, paving the way for optimizing hygienic protocols for viruses with similar structure, such as SARS-CoV-2.