Effectiveness of Nanomaterial Copper Cold Spray Surfaces on Inactivation of Influenza A Virus

Abstract

Bacterial and viral contamination of touch surfaces allows for transmission of pathogens leading to increased risk of infection. Previous work has demonstrated the antimicrobial properties of copper for contact-killing of microbes for use in hospitals. Less research exists on copper as an antiviral surface and on the effects of nanomaterial copper surfaces in the contact-killing of viruses. Nano agglomerate and conventional copper powder feedstock is used in the cold spray process to form copper coatings on aluminum substrates. The nano and conventional copper surfaces formed are tested for antiviral contact-killing of influenza A virus. After a two hour exposure to the surfaces, the surviving influenza A virus was assayed and the results compared. The differences in the powder feedstock used to produce the test surfaces were examined in order to explain the mechanism that caused the observed differences in influenza A virus killing efficiency. Results showed that the nano copper surface was antiviral, but less effective than a study on antimicrobial killing of MRSA on copper surfaces. The nano copper surface was more effective at percent reduction of influenza A virus than that of conventional copper. It was determined that the work hardening caused by the cold spray process in combination with the high number of grain boundaries results in a copper microstructure that enhances ionic diffusion. Copper ion diffusion is the principle mechanism for microbial and viral destruction on copper surfaces. Testing determined significant microbiologic differences between nano-and conventional Cu surfaces and demonstrates the importance of nano copper surfaces as an antiviral agent. The nano agglomerate powder shows superior antiviral effectiveness to that of conventional Cu due to an increase in grain boundaries at the nano level. Further research is needed to determine the effects of nano and conventional copper surface roughness on the contact-killing rate of viruses versus microbes on both a micro and nano-scale.