29 March 2018

Antibacterial nanoeedles

Nature has once again become the prototype of a scientific invention. The wings of dragonflies and cicadas have a structural feature that protects them from bacteria: a nanolayer of pointed columns is located on the surface, which leads to damage to the shell of the bacterium and its death.

It is known that up to 80% of diseases are transmitted through the hands. Disinfection of surfaces helps to fight the spread of infection, but it must be carried out regularly. In addition, the products used for surface treatment may contain harmful chemicals, for example, triclosan. Another problem of disinfection is the formation of resistance of bacteria to it. Also, we should not forget about the environmental aspect.

Researchers from the Institute of Bioengineering and Nanotechnology in Singapore (Institute of Bioengineering and Nanotechnology (IBN) of A*STAR) proposed using a nanolayer of pointed columns to create an antibacterial coating that could prevent the spread of infection in public places. It could protect people when touching, for example, door handles or elevator buttons, especially in hospitals and polyclinics.

Antibacterial nanocoating. 
Here and further source: A*STAR.

To do this, Yugen Zhang and his group grew pointed nanostubes made of zinc oxide, known for its safety and antiseptic properties. This structure destroys a wide range of bacteria, including E. coli and Staphylococcus aureus.

Fragments of destroyed E. coli on the surface of the nanocoating.

Tests on ceramic, glass, titanium and zinc surfaces showed that the nanolayer killed up to 99.9% of microorganisms.

Mechanical destruction of bacteria has a number of advantages over chemical destruction: it is safe for humans, does not require any additional manipulations, and bacteria will not be able to resist it in any way and form resistance mechanisms.

Further study showed that antibacterial nanocoating works best on zinc surfaces. This is due to the fact that the chemical interaction of the surface with the nanostool material led to the release of reactive oxygen species, which significantly complemented the antibacterial effect.

Placing a zinc plate with a nanocoating in water containing E. coli led to the complete destruction of bacteria. This means that this technology can be used for water purification.

The authors hope that their invention will become the basis for a safe, inexpensive and effective way to combat the spread of diseases transmitted through dirty hands, and will also help in the future to defeat nosocomial infection.

Article by G. Yi et al. ZnO Nanopillar Coated Surfaces with Substrate-Dependent Superbactericidal Property is published in the journal Small.

Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on A*STAR: Dragonfly-inspired nano coating kills bacteria upon contact.

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