Spray Coating To Shield Surfaces From Viruses, Bacteria

A newly-developed sprayable coating may prevent the spread of COVID-19 and other viruses, according to researchers in Australia.

The first-of-its-kind spray has two-fold properties that not only repel viruses and bacteria through an air-filled barrier but also kill pathogens through microscopic materials if the layer of coating is damaged or submerged even for extended periods.

The spray is formulated from plastics as strong as bullet-proof glass.
It is described in the paper titled “Shielding Surfaces from Viruses and Bacteria with a Multiscale Coating” that appears in the journal Advanced Science.

Standard disinfectants are becoming less and less effective and require reapplication.

The new coating is the only permanent surface layer that has proven to protect surfaces from contamination by viruses, say the co-authors of the paper.

They claim it is safer than alternatives to disinfectant, has no harmful side effects, and is more stable in its potency than silver nanoparticles, which are the next most promising non-disinfectant anti-bacterial agent.

According to the authors, the innovative coating could be used on surfaces such as stair rails, elevator controls, and other surfaces in settings such as hospitals, nursing facilities, schools, and restaurants to prevent the spread of disease-causing pathogens.

Co-authors Antonio Tricoli and David Nisbet of the University of Sydney affirmed that contact with surfaces bearing viruses and bacteria is a leading cause of infection, and contributes to 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,” Tricoli said.

“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 nanomaterials dispersed in the coating,” Tricoli said.

Developed over the course of five years, the coating’s mechanical stability and surface energy were tested by the researchers. They also tested its ability to resist contamination from bacteria and viruses.

The samples were also submerged for extended periods of time and the sprayed surfaces were deliberately damaged to test the spray’s resilience against their contamination.

“We have identified the mechanical processes underpinning how the spray works and quantified its effectiveness in different environments,” Nisbet said.

“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 coating 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 is applied like spray paint, albeit in smaller quantities.

“The coating has been engineered through a simple and scalable technique with a careful choice of materials to provide ultra-durability.

“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,” Nisbet said.