Replica molds of cicada wings give flight to possibilities of antibacterial surfaces

Nature often provides solutions and inspirations for biomedical applications. Cicada wings, for example, have microscopic spikes that defend against invading bacteria, and may offer a blueprint for creating topographies that can combat antibiotic-resistant bacteria.

Flynn et al. made replicas of a cicada wing out of polyethylene glycol (PEG), as similar plastic and polymer surfaces commonly house bacteria. The replicas imitated the nano- and microscale ridges and spikes of cicada wings.

The authors were able to control the height of the spikes, or nanopillars, by adding specific amounts of water to the PEG, which could swell to form larger spikes. They created three nanostructured hydrogels of PEG using a mold, with 0%, 20% and 40% water, and produced surfaces with nanopillars of different heights and thickness in the same range as those found on cicada wings.

“This is a key step in understanding how to control the features of polymer or plastic surfaces that have potential antibacterial activity,” said author Susan Kelleher. “We are still trying to understand the size and shape of features which are the best at killing bacteria cells.”

The authors believe different spike sizes and patterns will be needed to target different bacteria. They plan to investigate how changes in spike pattern on a plastic or polymer surface would affect its antibacterial ability. They will also create metal replicas of the wings, which can be made in large quantities, to help build a library of spiked metal and polymer surfaces.

Source: “Replica molding of cicada wings: The role of water at point of synthesis on nanostructure feature size,” by Shauna P. Flynn, Stephen Daniels, Brian J. Rodriguez, and Susan M. Kelleher, Biointerphases (2020). The article can be accessed at https://doi.org/10.1116/6.0000637 .

This paper is part of the Biomimetics of Biointerfaces Collection, learn more here .