CORRISON Editorial Calls for Experimental Research to Boost Copper Alloys’ Antimicrobial Properties

As humans rally against the spread of COVID-19, the best defense remains to wash our hands. Even with diligent handwashing, however, touching infected surfaces risks infection. Coating surfaces with antimicrobial materials offers a more enduring protection against indirect transmission of the virus.

In an editorial published in CORROSION, John R. Scully calls on fellow experts to pursue research and experimentation in copper alloys. Scully, the Charles Henderson Chaired Professor of Materials Science and Engineering at the University of Virginia, chairs the Department of Materials Science and Engineering. He is also technical editor in chief of CORROSION, a peer-reviewed journal dedicated to the science and technology of corrosion prevention and control.

Scully began working on the editorial after reading a New England Journal of Medicine article about the stability and estimated decay rates of SARS-CoV-2 and SARS-CoV-1 in aerosols and on various surfaces, specifically plastic, stainless steel, copper and cardboard.

“There was a great deal of fear over how long the virus would survive and remain viable on various surfaces that people handle every day, such as in their groceries and mail,” Scully said. “I realized I could use my role as an editor and technical ambassador to clarify the materials’ role, focusing on the mechanisms behind copper’s anti-microbial benefits.” 

Faculty and students in UVA’s Center for Electrochemical Science and Engineering have worked on anti-microbial copper alloys for many years with funding from industry partners such as the Copper Development Association and government agencies such as the National Science Foundation. Alloys’ anti-microbial properties involving electrochemical reactions on copper is one area of the center’s research.

Electrochemical corrosion reactions not only produce anti-microbial copper cations (i.e., positively charged ions), but also produce chemicals such as peroxides often used as disinfectants; biocide production is a natural consequence of the metal’s exposure to its environment. The trick is to control the corrosion process deliberately and precisely, to release copper ions from the alloy on the spot and in the same local environment where the virus lives.

The center’s research team also seeks optimal alloying—to simultaneously achieve a number of properties for widespread acceptance and utilization. “We have always felt that anti-microbial copper alloys could be a big benefit in public places and hospitals,” Scully said. “People want a material that looks like stainless steel or aluminum, but these materials have no anti-microbial capability.”

Scully argues for research to develop a copper alloy surface coating for frequently touched objects that is sufficiently corrosive to mitigate virus viability, but also retains its shine, can be cleaned, and is non-porous. Scully presents a five-point research plan to achieve this goal:

1) trace the fate of copper when it is oxidized and released;

2) truly understand whether a particular copper alloy and its environment come together to activate copper’s antimicrobial properties;

3) test copper alloys at a range of temperatures, surface conditions and relative humidity to identify the conditions at which copper alloys are most effective at fighting harmful microbes and viruses;

4) understand the survivability of bacteria and viruses in a systematic way in different environments and at various temperatures to guide antimicrobial alloy development; and

5) investigate real-world settings where specific copper alloys successfully reduce virus viability and indirect human transmission.

The search for optimal alloys is an “all-of-the above” approach to mitigate disease transmission and infection and depends on experts at the intersection of public health and materials science. UVA’s materials scientists and engineers are doing their part. They seek to explore the fate of copper in different product forms and processed in different ways, which could lead to specifications for anti-microbial use.

“This discussion is about the essential attributes generic to a range of alloys required for the material to work in this way,” Scully said. “We’re really focused on functionality—does the anti-microbial function turn on and off, and how, and why?”

Whereas early research in the effectiveness of copper alloy surfaces with respect to COVID-19 is promising, further investigation focusing on material properties, surface preparation and environments may uncover additional ways to enhance antimicrobial properties.

“I started the editorial as a public service announcement to address immediate concerns about anti-microbial efficacy, but it ended up broadening my perspective on needs, gaps and opportunities” Scully said. “The key is to maintain momentum in materials science and engineering for public health after the crisis has passed, to fully understand anti-microbial functionalities and generate novel materials to mitigate infection.”