The Times - UK (2020-07-21)

the times | Tuesday July 21 2020 2GM 25

News

Good hunting This image of a buzzard and peregrine falcon was found for the first
time by Peter Orr while organising his 400,000-picture archive. He took it in 2014

The delicate wing of the cicada,
translucent and almost impossibly thin,
is one of nature’s most beautiful
structures. Not, though, from the view
of bacteria. Then it is neither exquisite
nor gorgeous — its surface is, instead, a
perilous kill zone that slices them open
without mercy.
Scientists have gained more insight
into how the insect does it, in the hope
of copying its tricks.
For cicadas, the antibacterial proper-
ties of their wings are likely to be just a
bonus. The nanostructure on the sur-
face probably evolved to make them
less reflective, and so help them to hide
from predators.
Less than a decade ago, though, sci-
entists found that it had a side benefit.
Any bacteria that landed on the wings

Cicada wings could help us to beat bacteria

were rapidly killed. This was not a

chemical attack but something about

the surface structure of the wing itself

that disrupted bacteria’s cell mem-

branes and tore them apart.

If we could copy that structure, re-

searchers thought, then it would be

possible to make longer-lasting anti-

bacterial surfaces without the need to

repeatedly use chemicals.

“Chemicals lead to a stronger strain

of bacteria,” Takeshi Ito, from Kansai

University, said. “They can become

immune to chemicals, but with this you

are physically killing them.”

Just as humans can get better at

coping with a disease but not a sword

slashing them, so it is hard for bacteria

to evade a structural enemy. Professor

Ito’s research, published in the Royal

Society of Chemistry journal RSC

Advances, was an attempt to gain more

insight into how the cicada does this. In

particular, by using a dye that changed

colour when the bacteria were dead, he

and his team found that bacteria that

were more mobile were worst affected.

This suggested that the flagella of

bacteria, which they use to propel

themselves, were getting entangled. As

the bacteria writhed on the wing’s sur-

face, its membranes were slashed open.

Professor Ito and his colleagues hope

to recreate this effect with a film they

have modelled on cicada wings. “The

film can be coated on materials that

large numbers of people touch in every-

day life,” he said.

He and his colleagues hope that they

may also be able to find ways to improve

on the design — something that might

be possible if, as they think, the bacteri-

cidal properties of cicada wings came

about by chance rather than evolution.

Fighting antibiotic resistance often

involves looking for ideas in the envi-

ronment. Many antibiotics come from

the natural world. Laura Fisher, from

the Royal Society of Chemistry, said:

“Antimicrobial resistance remains one

of humanity’s biggest threats. We are

always amazed by how much more we

have to learn from nature. Professor

Ito’s work is an example of how

chemistry is always finding new

solutions, even in unexpected places.”

Tom Whipple Science Editor

2

1

Bacterium

Cicada

Cicadidae, Neotibicen

Structure of

wing surface

Flagella

1 Bacterium’s

flagella get

caught and trapped

on nanostructure of cicada wing

2 Trapped bacterium rubs on surface,

breaking up

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