Nano copper takes the fight to coronavirus

In further investigation into the natural antimicrobial properties of copper, researchers at the University of Waterloo, Ontario, have discovered that using a thin-film coating of copper or copper compounds can enhance the metals' natural ability to inactivate or destroy bacteria and viruses, including the SARS-CoV-2 virus responsible for COVID-19, by saturating contamination with nano-copper.

In a study that began soon after the pandemic hit in March 2020, University of Waterloo engineering graduate students began examining how six different thin metal and oxide coatings interacted with HCov-229E, a coronavirus that is genetically similar to SARS-CoV-2 but relatively safer to work with.

"While there was already some data out there on the lifetime of the virus on common-touch surfaces like stainless steel, plastics and copper, the lifetime of the virus on engineered coatings was less understood," said Kevin Musselman, the Waterloo mechanical and mechatronics engineering professor who led the study.

The Waterloo team partnered with Wilfrid Laurier University researchers, who tested the effectiveness of the antiviral coatings on glass and N95 mask fabric.

This testing involved depositing coatings that were about 1,000 times thinner than a human hair, then immersing the coated glass and fabric in a viral solution or exposing them to smaller droplets of the viral solution.

After removing the virus from the coatings, each extraction was placed in contact with healthy cells and measured for its ability to replicate.

Results showed the other coatings did not have the same antiviral effects as copper or a copper-containing compound.

Furthermore, they found that in some cases, "nanoscale thin films of copper can come off from the surface and rapidly dissolve in virus-containing droplets, enhancing the virucidal effect," said lead study author Louis Delumeau, who recently graduated from Waterloo with a master's in nanotechnology engineering.

"There is an opportunity to tailor the coating in a way that enhances its interaction with the viral droplet and the antiviral effect," added Musselman.

In any event, this is not the first time copper has been pursued for its virus-killing properties. Teck Resources Ltd. has long been endeavoring to develop a means of protecting high-touch areas by coating common locations with a copper coating.

Corning Inc. and PPG have partnered to develop an antimicrobial paint that captures the strengths of copper in an effective and stylish coating.

Even UK-based company Copper Clothing Ltd. has jumped into the known properties of copper to develop its line of copper-laced textiles.

Yet, this recent announcement by the Waterloo team is potentially a breakthrough in the mechanisms that copper exhibits that will allow scientists to develop more effective means of countering transmission of such dangerous microorganisms.

As some attempt to develop metallic stickers or sealants, Waterloo researchers have opted toward masks.

"Not only would a mask that covers the nose and mouth greatly limit the transmission of the virus but adding a coating such as the one we developed could actually kill the virus rapidly and reduce the amount of virus spread," said Delumeau.

The scientists are presently developing coating techniques for masks and are continuing to explore the dissolution process for smaller droplet sizes, as well as investigating how to control the adhesion of copper films to various surfaces.