February 7, 2023

Left: Scanning electron microscopy image of the CuNW network on a copper-sprayed surface. Right: Close-up of CuNW nanowire, about 60 nm in diameter, about 100x smaller than a human hair. Credit: US Department of Energy Ames National Laboratory

An old metal used for its microbial properties forms the basis for a materials-based disinfection solution. A team of scientists from Ames National Laboratory, Iowa State University and University at Buffalo has developed an antimicrobial spray that deposits a layer of copper nanowires on high-touch surfaces in public spaces. The spray contains copper nanowires (CuNWs) or copper-zinc nanowires (CuZnNWs) and can form an antimicrobial coating on various surfaces. This research was initiated by the COVID-19 pandemic, but the findings have broader applications.

Humans have used copper’s antimicrobial properties since 2400 BC to treat and prevent infections and disease. It has been proven effective for inactivating viruses, bacteria, fungi and yeasts when they come into direct contact with the metal. According to Jun Cui, a scientist at Ames Lab and one of the lead researchers on the project, “copper ion can penetrate the membrane of a virus and then insert itself into the RNA chain, completely disabling the virus to duplicate itself.”

Amid the pandemic, “The DOE asked researchers, what can you do to mitigate this COVID situation?” said Cui. Ames Lab is known for its work in materials science, not a field that often intersects with disease research. However, Cui’s team came up with the idea of ​​applying copper’s antimicrobial properties to help reduce the spread of COVID.

Cui explained that their idea came from a separate project they were working on, which was a copper ink designed for printing copper nanowires used in flexible electronic devices. “So the thought is, this is ink, and I can dilute it with water or even ethanol, and then just spray it. Whatever the surface, I spray it once and cover it with a very light layer of copper nanowire,” he said.

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First, the surface must be cleaned and disinfected, after which the reformulated copper ink solution can be applied. The ideal coating should be thin enough to be transparent. The ink can be diluted with water or alcohol to make it sprayable, and it works on plastic, glass and stainless steel surfaces.

The team tested two types of copper ink, CuNW and CuZnNW. Compared to a regular copper disc, both inks were just as effective at eliminating the virus. However, it took 40 minutes for the copper disk to eliminate the virus, while the copper inks only took 20 minutes. The nanowires worked faster because of their larger surface area.

In a comparison between the two ink coatings, the CuNW inactivated the virus faster than CuZnNW during the first 10 minutes. However, CuZnNW had a more steady and sustained release of copper ions compared to CuNW, keeping the coating effective for longer. In the end, the team concluded that the CuZnNW was the best option for a sprayable copper nanowire coating for antimicrobial purposes.

Cui said this work was important not just because of the pandemic, but because these nanowires can protect against many different microbes, “there’s a chance we could have a lasting impact on human society.”

This research is further discussed in the article “Sprayable copper and copper-zinc nanowire inks for antiviral surface coating,” by C. Pan, KS Phadke, Z. Li, G. Ouyang, T.-h. Kim, L. Zhou, J. Slaughter, B. Bellaire, S. Ren and J. Cui and published in RSC Progress.

Portable antimicrobial copper nanomesh sticks to human skin and kills microbes almost instantly

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More information:
Chaochao Pan et al, Sprayable Copper and Copper Zinc Nanowire Inks for Antiviral Surface Coating, RSC Progress (2022). DOI: 10.1039/D1RA08755J

Provided by Ames Laboratory

Quote: Scientists use copper nanowires to fight the spread of disease (2022, July 27) retrieved July 27, 2022 from https://phys.org/news/2022-07-scientists-copper-nanowires-combat-diseases.html

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