A combined team of researchers from Spain and Australia has discovered what they claim is the first known instance of a biomaterial that can kill bacteria on contact based only its physical surface structure. In their paper published in Biophysical Journal, the team describes how they found that clanger cicadas have nanoscale sized pillars on their wings that trap and slowly kill bacteria by pulling their cells apart.Under a microscope, the team reports, the wings of the clanger cicada show a landscape hostile to bacteria—vast arrays of blunted spikes. When bacteria land on the spikes, they don't pop, as might be expected, instead, they stick and are slowly torn apart as their cell skin descends to the wing surface between the spikes. It works because at least some bacteria have elastic skin.
It's similar to a water balloon landing on a bed of blunt nails. The nails aren't sharp enough to pierce the balloon's skin, but over time, as the weight of the water inside the balloon pushes the skin between the spikes, causing it to stretch, tears eventually develop, causing the balloon to deflate, or in the case of the bacteria on the cicada's wing, death.