Credit: CC0 Public Domain
A team of international researchers used liquid gallium as a catalyst to make an antiviral, antimicrobial coating. They also tested it on various fabrics including facemasks. The coating was more durable than conventional metal coatings and eliminated 99 percent of common pathogens in just five minutes.
"Microbes can live on the fabrics hospitals use to make their bedding, clothing, and face masks for a very long time," said Michael Dickey (co-author of a paper about the work and Camille & Henry Dreyfus Professor in Chemical and Biomolecular Engineering at North Carolina State University). Although metallic surface coatings like copper and silver can be effective in eliminating these pathogens, many metal particle coating technologies have problems such as poor adhesion, processing complexity, non-uniformity or poor adhesion.
Dickey, along with colleagues from NC State, Sungkyunkwan University, (SKKU), in Korea, and RMIT University, Australia, set out to create a simple and cost-effective method to deposit metal coatings onto fabric.
The researchers first placed liquid gallium (Ga), in an ethanol solution, and then used sound wavesa process called sonicationto make Ga nanoparticles. After the nanoparticle solution had dried, it was applied to the fabric. The Ga then adhered to the fibers.
The researchers then dipped the Ga-coated fabric in a copper sulfate solution to create a spontaneous galvanic substitution reaction. The reaction deposits copper onto fabric, creating a coating made of liquid copper alloy nanoparticles.
The research team exposed the fabric and its antimicrobial properties to three common microbes, Staphylococcus aureus (escherichiacoli), Candida albicans (cause unknown), in order to test their effectiveness. These microbes thrive on fabrics that are not coated. Copper alloy-coated fabric eliminated over 99% of pathogens in five minutes. This was significantly faster than the effectiveness of control samples that were only coated with copper.
To prove that coatings can also be used against viruses, the team worked with Elisa Crisci (assistant professor of virology at NC State) and Frank Scholle (assistant professor of biological sciences, at NC State). The coatings were tested against H1N1 and coronavirus (HCoV 229.E), which are both members of the same family as SARS. After five minutes, the coatings eliminated all viruses.
"Our tests show that these liquid metal-copper-coated fabrics demonstrate superior antimicrobial performances compared to other copper-coated surfaces and two commercially antimicrobial facemasks which rely on silver and copper respectively," Vi Khanh Truong is a Vice Chancellor's Fellow at RMIT University and visiting Fulbright Scholar. He was also the co-author of the research.
Ki Yoon Kwon is a postdoctoral associate at SKKU, and the first author of this work.
Taeil Kim, coauthor of the research and professor at SKKU, says that it could work with other metals like silver. It is also simple and should be easy to scale up for mass production.
This research is published in Advanced Materials. It was supported by the National Research Foundation of Korea. Samuel Cheeseman, a Fulbright Scholar visiting RMIT University, also contributed to this work.
Ki Yoon Kwon and colleagues, A liquid metal mediated metallic coating for antimicrobial or viral fabrics, Advanced Materials (2021). Information from Advanced Materials Ki Yoon Kwon and colleagues, A Liquid Metallic Mediated Metallic Coating For Antimicrobial And Antiviral Fabrics (2021). DOI: 10.1002/adma.202104298
