Coming soon: Coating on phones, keyboards will kill Covid, other viruses in minutes
3 min read 29 Aug 2022, 01:14 PM ISTThe durable and safe-to-use coating, which could be a game changer in traditionally germ-laden public spots such as hospitals and airports, killed 99.9% of microbes
PremiumA durable and safe-to-use coating that is expected to kill the Covid-19 causing SARS-CoV-2 virus – E coli and MRSA bacteria – and several other pathogens within minutes has been developed by researchers at the University of Michigan.
The durable coating, which could be a game changer in traditionally germ-laden public spots such as hospitals and airports, killed 99.9% of microbes even after months of repeated cleaning and abrasion on real-world surfaces including keyboards, mobile phone screens and chicken-slathered cutting boards.
Anish Tuteja, a professor at the University of Michigan, said that disinfectant cleaners can kill germs in only a minute or two, but they dissipate quickly and leave surfaces vulnerable to reinfection.
"We do have long-lasting antibacterial surfaces based on metals like copper and zinc, but they take hours to kill bacteria. This coating offers the best of both worlds," Tuteja, who is a co-corresponding author of the research published in the journal Matter, noted.
Coating uses antimicrobial molecules
The researchers further said that the coating, which is clear and can be brushed or sprayed on, uses antimicrobial molecules extracted from tea tree oil and cinnamon oil.
Both these derivates used for centuries as safe and effective germ killers that work in under two minutes.
The coating's durability comes from polyurethane, which is a tough, varnish-like sealer that is frequently used on surfaces like floors and furniture.
Tuteja added, "The antimicrobials we tested are classified as 'generally regarded as safe' by the FDA, and some have even been approved as food additives."
"Polyurethane is a safe and very commonly used coating. But we did do toxicity testing just to be sure, and we found that our particular combination of ingredients is even safer than many of today's antimicrobials," he explained.
Coating could keep killing germs for 6 months/ more
The outcome of the study's durability tests propose that the coating could keep killing germs for six months or more before its oil begins to evaporate and diminish its disinfectant power.
However, even then, Tuteja said it can be recharged by wiping it with fresh oil which is reabsorbed by the surface, starting the cycle again.
He estimates that the technology could be commercially available within 365 days.
The main challenge in making the coating was to combine the oil and polyurethane in a way that let the oil molecules do their germ-killing work, while preventing them from evaporating quickly.
It has been licensed to Hygratek, a spinoff company that Tuteja founded with assistance from the University of Michigan Innovation Partnerships.
The team, including associate professor Geeta Mehta, and materials science and engineering PhD students Abhishek Dhyani and Taylor Repetto, found a possible solution in cross-linking, a well-known process that uses heating to link materials together at the molecular level.
The smaller oil molecules readily combined with the cross-linking polymer molecules, forming a stable matrix, the researchers said.
However, to kill germs, the oil molecules need to penetrate their cell walls, which they can't do if they are tightly tethered into the matrix.
Eventually, they found a middle ground by partially cross-linking the materials -- enough to keep some of the molecules free to do their work, but keeping others bound tightly to the polyurethane.
"There was some trial and error, but we eventually found that cross-linking only some of the oil did what we needed," Tuteja said.
"The free oil tends to stay with the oil that's cross-linked into the matrix, helping the coating last longer," he said.
Once the basic recipe was set, the researchers set about finding a combination of active ingredients that would kill a wide variety of the germs that trouble humans most.
To identify a representative sample of microbes, the team found a precise balance of antimicrobial molecules that were effective, safe and inexpensive.
He said that the team's understanding of individual ingredients' properties enables them to tweak the formula for specific applications or rebalance the antimicrobial agents to kill specific germs.
"It's never our goal just to develop a one-off coating, but instead to develop a library of underlying material properties to draw from," Tuteja went on to add.
"If we can understand those properties, then we can develop coatings to meet the needs of specific applications," Tuteja noted.
With agency inputs
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