Self-Cleaning Surface Repels Drug-Resistant Bacteria

A new study shows how a flexible plastic wrap that combines a hierarchical wrinkled structure with chemical functionalization can reduce bacterial adhesion, biofilm formation, and the transfer of bacteria through an intermediate surface.

Developed by researchers at McMaster University (Hamilton, ON, Canada), the new plastic surface, which resembles conventional cling-wrap, is based on hierarchical wraps that can reduce Gram positive methicillin-resistant Staphylococcus aureus (MRSA) and Gram negative Pseudomonas aeruginosa colonization by 87% and 84%, respectively. The effectiveness of the surface was studied using electron microscope images, which showed that virtually no bacteria could transfer to the new surface. In addition, the surfaces remain free of bacteria even after coming into contact with a surface contaminated with Gram negative E. coli.

The antibacterial properties are the result of broad liquid repellency of the engineered surfaces, and the presence of reduced anchor points for bacterial adhesion on the hierarchical structure. The wrap, which is fabricated using scalable bottom-up techniques, can form an effective cover on a variety of complex objects, making them superior to top-down and substrate-specific surface modification methods. The wrap can be applied onto door handles, railings, intravenous (IV) stands and other surfaces. The treated material is also ideal for food packaging, where it could stop the accidental transfer of bacteria from raw chicken, meat and other foods. The study was published on December 13, 2109, in ACS Nano.

“Inspired by the water-repellent lotus leaf, the new surface works through a combination of nano-scale surface engineering and chemistry; the surface is textured with microscopic wrinkles that exclude all external molecules,” said senior author Leyla Soleymani, PhD, of the department of mechanical engineering. “We're structurally tuning that plastic; a drop of water or blood, for example, simply bounces away when it lands on the surface. The same is true for bacteria. This material gives us something that can be applied to all kinds of things.”

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