It killed 99.9% of microbes even after months of repeated cleaning, scrubbing, and other real surfaces like keyboards, cell phone screens, and chicken cutting boards.
The coating could be a game changer in traditionally germ-ridden public spaces like airports and hospitals. Anish Tutejaprofessor of materials science and technology at UM and corresponding author of the article published in Matter.
“We’ve never had a good way of keeping high-touch surfaces like airport touchscreens clean,” he said. “Disinfectants can kill bacteria in just a minute or two, but they evaporate quickly and leave surfaces vulnerable to reinfection. We have long-lasting antibacterial surfaces based on metals like copper and zinc, but they take hours to kill. This coating offers the best of the options.”
The coating, which is clear and can be brushed or sprayed, gets its durability and germ-killing power by combining proven ingredients in a new way. It uses antimicrobial molecules derived from tea tree oil and cinnamon oil, which have been used for centuries as safe and effective germ-killing agents that work in less than two minutes. The coating’s durability comes from polyurethane, which is a hard, varnish-like sealant commonly used on surfaces such as floors and furniture.
“The FDA has classified the antimicrobials we tested as ‘generally considered safe,’ and some have even been approved as food additives,” Tuteja said. “Polyurethane is a safe and very commonly used coating. But we did toxicity testing just to be sure, and we found that our particular combination of ingredients is even safer than many current antimicrobials.”
The results of the study’s durability tests suggest that the coating could kill bacteria for six months or longer before its oil begins to evaporate and reduce its ability to disinfect. But even then, Tuteja says it can be recharged by wiping it with fresh oil; new oil is reabsorbed to the surface and the cycle begins again.
Tuteja estimates that the technology could be commercially available within a year; it is licensed to Hygratek, a spinoff company founded by Tuteja with the help of UM Innovation Partnerships.
The key challenge was to combine oil and polyurethane in such a way that the oil molecules can do their job of killing bacteria and prevent them from evaporating quickly. The research teamโincluding Geeta Mehta, assistant professor of materials science and engineering and biomedical engineering, corresponding author; and for doctoral students in materials science and technology Abhishek Dhyani and Taylor Repetto, the first authors – found a possible solution in cross-linking, a well-known process that uses heating to join materials at the molecular level. Smaller oil molecules were combined with easily crosslinkable polymer molecules, forming a stable matrix.
But to kill bacteria, the oil molecules must penetrate their cell walls, which they cannot do if they are firmly attached to the matrix. In the end, they found a middle ground by partially cross-linking the materialsโenough to keep some of the oil molecules free to work, but keep others tightly bound to the polyurethane.
“It took some trial and error, but eventually we found that just cross-linking some of the oil did what we needed,” Tuteja said. “The free oil tends to stay in the matrix cross-linked oil, which helps the coating last longer.”
Once the basic recipe was set, researchers began to find a combination of active ingredients that would kill a wide variety of bacteria that plagued people the most. They worked with corresponding authors to identify a representative sample of microbes Christiane E. Wobusassistant professor of microbiology and immunology, and J. Scott VanEpps, assistant professor of emergency medicine, both at UM Medical School. Eventually, they found a precise balance of antimicrobial molecules that were effective, safe, and affordable.
Tuteja emphasizes that they are not tied to a specific formula; The team’s understanding of the properties of individual ingredients allows them to adjust a formula for specific uses or balance antimicrobials to kill specific bacteria.
“Our goal is never to develop just a single coating, but instead to develop a library based on the underlying material properties,” said Tuteja. “If we understand these properties, we can develop coatings to meet the needs of specific applications.”
HT
Source: ANI
Source: The Nordic Page