Aim: COVID-19 caused by a new coronavirus, SARS-CoV-2, has become an ongoing worldwide pandemic. A safe and potent virucidal disinfection system is urgently needed to protect the population from the virus. Chlorine Dioxide (ClO2) is a powerful disinfectant that is known to inactivate both viruses and bacteria. The aim of this study was to investigate whether chlorine dioxide inhibits the binding of the receptor-binding domain of the Spike protein (S protein) from variant coronavirus (British and South African variants) to human receptor, Angiotensin-Converting Enzyme 2 (ACE2).
Materials and Methods: In vitro experiments to determine binding of the purified receptor-binding domain of spike protein to ACE2 were performed in the presence of various concentrations of chlorine dioxide. Purified spike proteins from the British and South African variants were used. Spike protein coated onto a microtiter plate was treated with chlorine dioxide aqueous solution or chlorine dioxide spray solution.
Result: Binding of variant spike proteins was inhibited in a concentration-dependent manner (50% Inhibitory Concentration (IC50) of 7.6 μmol/L and 5.8 μmol/L for the British and the South African variants, respectively).
Conclusion: These findings show that chlorine dioxide aqueous solution can inactivate the binding of the variant spike proteins to the human ACE2 receptor protein, indicating that this strategy may be useful in blocking the transmission of variant SARS-CoV-2 viruses.