Scientists have discovered that a type of cicada features tiny spikes on its wings that kill bacteria.
The surface of the clanger cicada’s (Psaltoda claripennis) wings are covered in a microscopic hexagonal array of “nanopillars” that stretch bacteria coming into contact with it, and tearing the bacterial membranes.
The study reporting the discovery is published in the latest edition of the Biophysical Journal. Elena Ivanova, the lead author of the study from Swinburne University of Technology in Hawthorne, Victoria, Australia, explained to Nature that the nanopillars do not actually puncture the bacterial membranes. Instead, the action is similar to “the stretching of an elastic sheet of some kind, such as a latex glove."
“If you take hold of a piece of latex in both hands and slowly stretch it, it will become thinner at the center, [and] will begin to tear,” Ivanova said. When a bacterium comes into contact with the cicada’s wing, its cellular membrane attaches to the nanopillar spikes, and the membrane fills in the gaps between the nanopillars.
The team irradiated bacteria in order to achieve different levels of rigidity, hypothesizing that the more rigid a bacterium’s membrane was, the less likely it was to rupture on the nanopillars. Their assumption was correct: the bacterium’s membrane had to be sufficiently soft for the nanopillars to rupture it.
The clanger cicada’s wing is one of the first structures observed that kills bacteria using only its physical form. The discovery could lead to new methods of anti-bacterial sterilization on man-made surfaces in public spaces, like handrails on public transportation or park benches. The detergents and cleaners currently used can be harmful to the environment and require regular reapplication. Building a bacteria-killing structure on the surface of an object means it would not need to be recoated or reapplied.
For a visual description of the clanger cicada’s wing structure rupturing bacteria, check out the video below:
