Self-cleaning surface repels bugs: researchers

Canadian researchers say they have developed a self-cleaning surface that can repel all forms of bacteria in pretty well any setting.

Essentially a treated form of conventional transparent wrap, they suggest that it could be shrink-wrapped onto door handles, railings, IV stands and other surfaces that can be magnets for all manner of bacteria.

It is particularly suited to food packaging, they note in a paper in the journal ACS Nano.

The research was led by engineers Leyla Soleymani and Tohid Didar from McMaster University, who worked with colleagues experienced in infections disease research and electron microscopy. 

Inspired by the water-repellent lotus leaf, the new surface works through a combination of nano-scale surface engineering and chemistry, they say. 

The surface is textured with microscopic wrinkles that exclude all external molecules. A drop of water or blood, for example, simply bounces away when it lands on the surface. The same is true for bacteria.

“We’re structurally tuning that plastic,” says Soleymani, an engineering physicist. “This material gives us something that can be applied to all kinds of things.”

The surface is also treated chemically to further enhance its repellent properties, resulting in a barrier that is flexible, durable and inexpensive to reproduce.

The team verified the effectiveness of the surface by capturing electron microscope images showing that virtually no bacteria could transfer to the new surface.

“These hierarchical wraps were effective for reducing biofilm formation of World Health Organisation-designated priority pathogens Gram positive methicillin-resistant Staphylococcus aureus (MRSA) and Gram negative Pseudomonas aeruginosa by 87 and 84%, respectively,” the authors write. 

“In addition, these surfaces remain free of bacteria after being touched by a contaminated surface with Gram negative E. coli.”