First-of-its-kind spray protects surfaces against bacteria, viruses

SYDNEY, Australia — A first-of-its-kind spray could help shield people from touching germs everywhere they go, preventing illnesses and infections like COVID-19. Australian researchers developed the sprayable coating which they say can protect all sorts of surfaces from bacteria and viruses.

The spray wards off germs through an air-filled barrier and kills pathogens through microscopic materials that spring into action if something damages the protective coating. Researchers say the spray uses a combination of plastics which are so strong, they could be an alternative to bulletproof glass.

The team spent five years developing the spray coating. It provides a valid alternative to standard disinfectants and is also much safer, more potent, and does not cause harmful side-effects. Researchers say the spray coating is the only permanent surface layer proven to protect surfaces from contamination by viruses.

They note that the coating would work in public settings such as hospitals, nursing homes, schools, and restaurants — protecting everything from staircase railings to dining room tables. A leading cause of infection is the spread of viral or bacterial pathogens through surface contact. This type of contamination also plays a role in the evolution of antibiotic-resistant bacteria.

“Without a barrier, viruses such as coronaviruses can stay on surfaces and remain infectious for up to a week. Other viruses such as reoviruses, which can cause colds or diarrhea, for instance, can remain on surfaces for several weeks, causing large outbreaks in health and aged care facilities,” explains study author Antonio Tricoli, a professor at Sydney’s School of Biomedical Engineering, in a university release.

“Like a lotus leaf, the surface spray creates a coating that repels water. Because the pathogens like to be in water, they remain trapped in the droplets and the surface is protected from contamination. If this mechanism fails, a secondary burst of ions is triggered by carefully designed nano materials dispersed in the coating.”

How does the spray work?

For the study, researchers tested the coating’s mechanical stability and surface energy. They also analyzed the coating’s ability to resist contamination from bacteria and viruses by subjecting it to high concentrations of both. Researchers submerged the samples for extended periods of time and intentionally damaged sprayed surfaces to test the coating’s resilience against contamination.

“We have identified the mechanical processes underpinning how the spray works and quantified its effectiveness in different environments,” says study co-author Professor David Nisbet, director of the University of Melbourne’s Graeme Clark Institute.

“For this study, we tested metal surfaces. However, in the past we have shown the spray can be applied to any surface, for example, blotting paper, plastic, bricks, tiles, glass and metal. Our eating successfully prevented up to 99.85 percent and 99.94 percent of the bacteria strain growth. We also saw an 11-fold reduction in virus contamination.”

The spray coating is applied in the same way as spray paint, however, you only need a small amount to get the job done.

“The coating has been engineered through a simple and scalable technique with a careful choice of materials to provide ultra-durability,” says Nisbet. “We also believe our explanation of the mechanism behind the antimicrobial and antiviral effects could significantly advance research in antipathogen technologies that could see affordable manufacture of an effective surface spray to protect people from viruses and bacteria.”

Researchers hope to make the spray available commercially within the next three years.

The study is published in the journal Advanced Science.