Thermal Spray Copper Alloy Coatings as Potent Biocidal and Virucidal Surfaces

Microbial and viral pathogen contamination of touch surfaces contributes to the rapid transmission of diseases. It has been known for decades that microbes and viruses are rapidly inactivated when exposed to copper and its alloys. Consequently, the use of thermal spray technologies to coat surfaces in healthcare and public settings has been receiving a considerable amount of interest during recent viral pandemics and particularly now with COVID-19. This review is focused on recent successes using thermal spray technology to uniformly coat metal and organic surfaces, providing a rapid and economical means of inhibiting fomite transmission of pathogens on diverse surfaces with complex topographies. Emphasis is placed on the influence of lamella structure, porosity, and roughness of the coatings as it pertains to biocidal activity and the implications of using this knowledge to optimize the ability of copper coatings to irreversibly inactivate viral pathogens, regardless of their genomic mutation rates. Results of the long-term performance of the copper alloy coatings in real hospital settings in Canada and Peru are also presented.