Insect wings inspire antibacterial packaging

Inspired by the bacteria-killing wings of insects like cicadas, scientists have developed a natural antibacterial coating for use in food packaging to improve shelf life and reduce waste.

The lab-made material kills up to 70 percent of bacteria and retains its effectiveness when transferred to plastic, according to the research published in ACS Applied Nano Materials.

More than 30 percent of food produced for human consumption becomes waste, with entire shipments rejected if bacterial growth is detected, according to the research. Creators of the new packaging hope to significantly reduce waste, particularly in meat and dairy exports, as well as extend the shelf life and improve the quality, safety and integrity of packaged food on an industrial scale.

“Eliminating bacterial contamination is a huge step in extending the shelf life of food,” said Professor Elena Ivanova of Royal Melbourne Institute of Technology (RMIT) University. “We knew the wings of cicadas and dragonflies were highly efficient bacteria killers and could help inspire a solution, but replicating nature is always a challenge. We have now created a nanotexturing that mimics the bacteria-destroying effect of insect wings and retains its antibacterial power when printed on plastic.”

The research – a collaboration between RMIT, Tokyo Metropolitan University and Mitsubishi Chemical’s The KAITEKI Institute – highlighted that dragonfly and cicada wings are covered by a vast array of nanopillars. These blunted spikes are similar in size to bacteria cells and when bacteria settles on a wing, the pattern of nanopillars pulls the cells apart, rupturing their membranes and killing them.

“It’s like stretching a latex glove,” Ivanova said. “As it slowly stretches, the weakest point in the latex will become thinner and eventually tear.”

The team of researchers developed their nanotexture by replicating insects’ nanopillars and developing nanopatterns of their own.

To assess the pattern’s antibacterial capability, bacteria cells were monitored at RMIT’s Microscopy and Microanalysis Facility. The best antibacterial patterns were shared with the Japan team, who developed a way to reproduce the patterns on plastic polymer.

Back in Australia, Ivanova’s team tested the plastic nanopatterns and found the one which best replicated insect wings while being easiest to fabricate and scale up.

Since Ivanova and her colleagues discovered the bacteria killing nature of insect wings almost a decade ago, they’ve been working to design the optimal nanopattern to harness insects’ bacteria-killing powers and use it on a range of materials.

The researchers stated that, until recently, it was difficult to find suitable technology to reproduce this nanotexturing on a scale suitable for manufacturing. However, now there is technology that enables the scale up and application of antibacterial properties to packaging, among a range of other potential applications, like personal protective equipment, according to the team.

Their new research builds on a 2020 study into the use of insect-inspired nanomaterials to fight bacteria on contact.

The team is keen to collaborate with potential partners in the next stage of the research – ie, upscaling the technology and determining the best ways to mass manufacture the antibacterial packaging.

“This is a big step towards a natural, non-chemical, antibacterial packaging solution for the food and manufacturing industry,” Ivanova added.