Physicochemical properties of SARS‐CoV‐2 for drug targeting, virus inactivation and attenuation, vaccine formulation and quality control

Abstract

The material properties of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its proteins are discussed. We review the viral structure, size, rigidity, lipophilicity, isoelectric point, buoyant density and centrifugation conditions, stability against pH, temperature, UV light, gamma radiation, and susceptibility to various chemical agents including solvents and detergents. Possible inactivation, downstream, and formulation conditions are given including suitable buffers and some first ideas for quality-control methods. This information supports vaccine development and discussion with competent authorities during vaccine approval and is certainly related to drug-targeting strategies and hygienics. Several instructive tables are given, including the pI and grand average of hydropathicity (GRAVY) of SARS-CoV-1 and-2 proteins in comparison. SARS-CoV-1 and SARS-CoV-2 are similar in many regards, so information can often be derived. Both are unusually stable, but sensitive at their lipophilic membranes. However, since seemingly small differences can have strong effects, for example, on immunologically relevant epitope settings, unevaluated knowledge transfer from SARS-CoV-1 to SARS-CoV-2 cannot be advised. Published knowledge regarding downstream processes, formulations and quality assuring methods is, as yet, limited. However, standard approaches employed for other viruses and vaccines seem to be feasible including virus inactivation, centrifugation conditions, and the use of adjuvants.

A Critical Review on Ultraviolet Disinfection Systems against COVID-19 Outbreak: Applicability, Validation, and Safety Considerations

“…The amino acid sequence of spike protein in SARS-CoV-2 is 76.47% identical to that of SARS-CoV, with the same structural conformation and electrostatic properties. 62 , 63 …”

Development of a Low-Cost Cotton-Tipped Electrochemical Immunosensor for the Detection of SARS-CoV-2

“…This is likely because of the shielding of the negatively charged carboxylic groups on the CNF surface with the antigen. It is worth noting that the reported isoelectric point of the N protein is 10.07, 32 indicating that the antigen carries a positive charge at pH 7.4.…”

On-Mask Chemical Modulation of Respiratory Droplets

“…A low pH environment (pH < 3) is generally suitable for disinfection because it denatures proteins and disrupts the lipid membrane in pathogens. 26 , 27 Ionic copper is a well-known broad-spectrum antimicrobial agent. 28 , 29 To enable loading of acid and copper ions on the nonwoven fabrics, the fibers are coated with a layer of conducting polymer polyaniline by in situ polymerization.…”