This story originally appeared in Stories of Australian Science 2014
Elena Ivanova and her fellow researchers at Swinburne University of Technology were studying self-cleaning surfaces in nature when they discovered bacteria being killed on the wings of the clanger cicada, Psaltoda claripennis
, a species mostly found in Queensland.
The secret seemed to lie in millions of tiny rounded spikes, or nanopillars, each a thousand times smaller than the width of a human hair.
“Imagine a water balloon sagging between blunt nails,” says Russell Crawford, one of Elena’s colleagues and dean of science. “The bacterial cell wall stretches between the nanopillars and eventually it breaks.”
They soon found similar structures on the wings of the wandering percher dragonfly, Diplacodes bipunctata. A chance conversation with an engineering colleague Saulius Juodkazis then led them to the ominously named black silicon, which was being evaluated for use in solar cells due to the light-absorbing qualities of its own spiky surface.
Both the dragonfly wings and black silicon are even better than cicada wings at killing bacteria, dispatching more varieties and even destroying their spores, which are otherwise nearly impossible to kill.
Because these surfaces shred the bacteria using a physical rather than chemical mechanism, they have great potential for use in hospitals, where antibiotic-resistant superbugs are a growing threat.
“We want to be able to create medical implants with antibacterial surfaces so that we can place them in the body without the risk of infection,” says Russell.