New surfaces kill bacteria by mimicking gecko skin

Signal of change / New surfaces kill bacteria by mimicking gecko skin

By George Armour / 07 Mar 2017

A team from the University of Queensland has created a surface that mimics the spikey physical structure of gecko skin that kills bacteria by puncturing their cell walls. In a world where there is a pressing need to develop new ways of fighting harmful bacteria, Microbe-resistant surfaces stand out as a particularly hopeful innovation. Initial designs focused on super-smooth surfaces but they were not fully effective as researchers found that they could not dislodge certain strains of bacteria. They instead turned to nature for inspiration.

Two Australian scientists, Greg and Jolanta Watson, have been researching naturally occurring antibiotic surfaces for decades. Using an electron microscope, they found that the physical structure of Gecko skin is comprised of intermeshing nanoscale pillars and larger pointed hair-like projections. These tiny protrusions puncture the cell walls of bacteria that try to settle on the surface, causing their innards to leak out and leading to their death. 

In late 2016, David Green, from the University of Queensland, saw the potential to harness these bactericidal properties and succeeded in creating large sheets synthetic gecko skin. His team did so by stamping soft polyvinyl with gecko skin to create moulds that can be filled with molten acrylic or various other materials. The resulting surface is almost as good as the original but the hairs are slightly shorter and more bulbous. Importantly, however, they still found the surface to be 88% effective against soft-shelled microbes and 66% against hard-shelled species.

So what?

Cases where microbes are resisting antibiotics are becoming increasigly common which points to a need to develop other ways to combat harmful microbes. For instance, in 2015 scientists identified a strain of E. coli found in samples from a slaughter house was resistant to colistin (a drug of last resort). 

The production of synthetic surfaces that possess bactericidal properties situations may offer a potential breakthrough as they do not use antibiotics but rather physics to kill bacteria cells. First, research has shown that the synthetic gecko skin surface is capable of dealing with biofilm (where lots of bacteria grow and clump up rendering it impossible to separate and resistant to antibiotics or chemicals) that is responsible for 80% of infections in clinical settings. There is strong potential for the application of this technology in the case of implants. Instead of relying on traditional chemical-based techniques, the implant itself could stop the build-up of biofilms if it is created with a gecko-like surface. Second, the technology is scalable. Real gecko skin is no longer being used to create the mould and it is now possible to print large sheets of the surface out of different materials.

If these surfaces become increasingly used what could be the consequences? As they have adapted to the use of drugs, bacteria and other microbes are sure to evolve resistance to physical antibacterial surfaces. Another concern comes out of the pro-biotic movement that sees exposure to different microbes as essential to human well-being. With that being said, the technology represents an interesting scalable solution of particular relevance for the medical world.

Sources

http://www.pbs.org/wgbh/nova/next/body/physics-antibiotics

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