Cleaning hands without water

Dirty hands can spread the germs that cause numerous diseases, and these diseases sicken millions worldwide each year. Current hand hygiene practices involve washing with soap and water and using antiseptic hand rubs, but both methods have drawbacks.

Now, researchers at Harvard T.H. Chan School of Public Health are suggesting a potentially more effective way to clean hands: using nano-aerosol mists, called engineered water nanostructures (EWNS), laced with antimicrobial agents.

The researchers described the method, based on technology they developed several years ago, in a November 10, 2019 paper in ACS Sustainable Chemistry & Engineering. They fine-tuned a cocktail of various “nature-inspired” antimicrobials, such as citric acid, hydrogen peroxide, and antimicrobial peptides, that could be sprayed as a super-fine EWN mist onto contaminated hands.

Compared to “wet” approaches, such as hand rubs and washing, the nano-aerosol killed as many or more pathogens in 30 seconds, the study found. Using this method could help address some of the issues with current hand-cleaning methods, such as the use of significant amounts of water, skin irritation from too much hand washing, or overexposure to chemicals in hand rubs, the researchers say.

“The chapter of infectious diseases is still open, unfortunately, to the contrary of what was believed decades ago with the invention of antibiotics,” said Philip Demokritou, director of Harvard Chan School’s Center for Nanotechnology and Nanotoxicology and senior author of the study. “New innovative approaches are needed in our continuous battle with infectious diseases and that’s where nanotechnology comes in play. The EWNS platform has the potential to be a disruptive technology which can be used to kill infectious microorganisms on surfaces and in the air in a sustainable manner.”

Learn more

Engineered Water Nanostructures (EWNS): A Novel Nanotechnology Based Method for Hand Hygiene (Center for Nanotechnology and Nanotoxicology press release)