Dragonfly Wings Inspire Antimicrobial Coating

Mimicking the structures of a dragonfly’s wings, a research group in Singapore has developed a nano-coating that can kill bacteria on surfaces as well as in water.

AsianScientist (Apr. 5, 2018) – Inspired by the wings of dragonflies, scientists in Singapore have invented an antibacterial nano-coating that could help to precent antimicrobial resistance. They published their findings in the journal Small.

80 percent of common infections are spread by hands. Disinfecting commonly touched surfaces helps to reduce the spread of harmful germs, but that entails frequent manual disinfection. Existing disinfectants often also contain chemicals like triclosan, which may not be safe or effective. Moreover, the extensive use of antimicrobial disinfectants may lead to bacterial resistance and environmental contamination.

Studies have shown that the wings of dragonflies and cicadas prevent bacterial growth due to their natural structure. The surfaces of their wings are covered in nanopillars making them look like a bed of nails. When bacteria come into contact with these surfaces, their cell membranes get ripped apart immediately and they are killed.

This inspired researchers from Singapore’s Agency for Science, Technology and Research (A*STAR) to invent an anti-bacterial nano coating for disinfecting frequently touched surfaces such as door handles, tables and lift buttons. Led by Dr. Zhang Yugen of the Institute of Bioengineering and Nanotechnology, the researchers grew nanopilllars of zinc oxide on various surfaces.

Tests on ceramic, glass, titanium and zinc surfaces showed that the coating effectively killed up to 99.9 percent of germs such as Escherichia coli and Staphylococcus aureus found on the surfaces. As the bacteria were killed mechanically rather than chemically, the use of the nano coating would not contribute to environmental pollution. Also, the bacteria will not be able to develop resistance as they are destroyed when their cell walls are pierced by the nanopillars upon contact.

The researchers also found that the nano-coating demonstrated the best killing activity when applied on zinc surfaces. This is because the zinc oxide nanopillars catalyzed the release of reactive oxygen species which could even kill nearby free-floating bacteria that were not in direct contact with the surface.

Subsequently, the researchers studied the effect of placing a piece of zinc that had been coated with zinc oxide nanopillars into water containing E. coli. All the bacteria were killed, suggesting that this material could potentially be used for water purification.

“Our nano coating is designed to disinfect surfaces in a novel yet practical way. This study demonstrated that our coating can effectively kill germs on different types of surfaces, and also in water. We hope to use this technology to create bacteria-free surfaces in a safe, inexpensive and effective manner, especially in places where germs tend to accumulate,” said Zhang.

The article can be found at: Yi et al. (2018) ZnO Nanopillar Coated Surfaces with Substrate-Dependent Superbactericidal Property.


Source: A*STAR; Photo: Pexels.
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