Revealing protein binding affinity on metal surfaces: an electrochemical approach

Revealing the binding affinity between viruses and surfaces of environmental matrices is crucial to evaluate the bioactivity of an immobilized virus and accompanying indirect virus-related infection pathways. The understanding for SARS-CoV-2 remaining infective for even days on stainless steel but only hours on copper is still unclear. Electrochemical chronoamperometry, ultrasensitive to interfacial capacitance on surface species, was used to investigate the binding affinity of SARS-CoV-2 on metal surfaces. S_RBD, the surrogate of SARS-CoV-2, shows the highest adsorption capacity on a gold surface, followed by Cu, but lowest on a stainless steel surface. The strong binding of S_RBD on copper is a result of the naturally grown Cu₂O under ambient conditions. Measurement of electrochemical capacitance provides a simple strategy to explore and evaluate the potential risk of an indirect virus-related infection pathway through conductive environmental matrices.