It doesn't take much to pick up a viral infection in spaces we share with other people – whether it's from tiny droplets in the air containing these particles, or touching doorknobs and countertops in offices and hospitals.
A material science breakthrough might help mitigate that using prickly spikes so small, you can't even see them.
Researchers at Australia's RMIT University have developed a nanostructured surface fabricated from silicon that's textured with ultra-fine nanopillars.
The antireflective material itself appears black to the naked eye, and the nanopillars have pointy ends that are so sharp, they pierce through the envelope of viral particles.
Once they're ripped open this way, the virus' infectivity is almost entirely eliminated over the course of six hours. That means that if we can coat high-touch surfaces with this material, we can greatly reduce the chance of spreading disease in shared spaces.
To test the effectiveness of this material, researchers placed droplets of human parainfluenza virus type 3 (hPIV-3), a common respiratory virus, onto silicon surfaces covered in millions of microscopic, sharp spikes and compared them to smooth, flat silicon surfaces for up to six hours.
Using powerful microscopes and laboratory tests to check for remaining infection, the team observed how the viruses interacted with these different textures. The experiment revealed that the tiny spikes acted like needles, physically puncturing the virus's fatty outer protective membrane, which caused the viral particles to deflate and lose their structural integrity.
While the viruses on the smooth surface remained largely intact and dangerous, the spiky surface destroyed 96% of the infectious virus within the six-hour window, demonstrating that this mechanical "nanospike" design can effectively kill pathogens without the need for toxic chemicals.
According to the researchers, who've looked at previous research into nanotextured materials, this could also destroy a host of other viruses like SARS-CoV-2, respiratory syncytial virus (RSV), rhinovirus (RV), and human coronavirus NL63 – though it's yet to be tested specifically against them. The material also proved to be effective at killing off certain bacteria in the same way, to an extent. We saw something similar with bactericidal stainless steel a couple of years ago.
The findings could pave the way for the development of new materials and surface coatings that can make a wide range of everyday objects safer to use.
"We could one day have surfaces like phone screens, keyboards and hospital tables covered with this film, killing viruses on contact without using harsh chemicals," said Samson Mah, the lead author of the study on this material that appeared in Advanced Science. "Our mold can be adapted to roll‑to‑roll manufacturing, meaning antiviral plastic films could be produced at scale with existing factory equipment."
It'll be interesting to see these insights carried forward and commercialized. There's work to be done yet in perfecting the nanotexture design to increase the efficiency of the material's ability to kill viruses. "When the nanopillars are closer together, more of them can press on the same virus at once, stretching its outer shell past breaking point," said Mah.
Source: RMIT University
