New Scientist - July 27, 2019

16 | New Scientist | 27 July 2019

Climate change

Secrets of how vital

drugs harm hearing

SOME life-saving antibiotics that

kill a broad range of bacteria can

also cause hearing loss, and we

may now know why.

Known as aminoglycosides,

these drugs are useful for treating

infections in newborns, which

can prove fatal within one or two

days, too soon for tests to reveal

the microbe responsible.

To better understand why this

class of antibiotics is linked with

Smart skin for

sensitive robots

AN ARTIFICIAL skin that senses

temperature and pressure can

send signals 1000 times faster

than the human nervous system.

Benjamin Tee at the National

University of Singapore and his

colleagues created the rubber

and plastic skin, which has tiny

sensors that can detect pressure,

bending and temperature.

When the skin presses against

something, the sensors transmit

electrical pulses back to one

receiver. Each sensor has a unique

pulse to make it identifiable,

meaning multiple signals can

be combined through the one

receiver, speeding up delivery.

Unlike in most electronic

systems, all of the sensors are

connected together using one

wire, meaning that measurements

from across the skin arrive at the

same time. Human skin sensors

send signals at a maximum

Bionics^ Antibiotics

PUMPING huge amounts of ocean

water onto the West Antarctic ice

sheet could stop it collapsing and

raising sea levels so much that they

would threaten cities like New York.

But researchers who explored the

idea admit the intervention would

require an unprecedented effort

in one of the harshest places on

the planet. It would cost hundreds

of billions of dollars and could

devastate ecosystems there.

Five years ago, studies suggested

that the West Antarctic ice sheet

had begun an unstoppable collapse.

While the process would take

centuries, it would raise sea levels

enough to hit major coastal cities.

So Anders Levermann of the

Potsdam Institute in Germany and

his colleagues simulated the idea

of pumping ocean water onto the

sheet, adding it either in liquid form

or as snow. They say stabilising

the collapse would require at least

7400 gigatonnes of the stuff

over 10 years (Science Advances,

doi.org/c8jg). Levermann says he

is against global geoengineering

such as giant sunshades, but this

idea is different and more surgical.

Even if we agreed to do it, there

are big obstacles. About 145GW

of wind farm capacity would be

needed to power pumps, 12 times

that installed in Europe last year.

New turbine materials would be

needed to cope with the cold and the

area would become an “industrial

compound”, says Levermann.

Clive Hamilton at Charles Sturt

University in Australia says: “The

conditions under which such a

scheme could be implemented are

beyond anything feasible. It’s not

going to happen.” Adam Vaughan

Drastic geoengineering

could help stem rising seas

hearing loss, Peter Steyger at

Creighton University in Nebraska

and his colleagues tested the

effects of one such drug,

gentamicin, on hearing in mice.

They found that infection and

inflammation left ion channels in

sensory hair cells (pictured) more

permeable to gentamicin, leading

to more of it being taken up by the

sensitive cells in the cochlea of the

inner ear. This amplified the toxic

effects of the drug on the cells.

Steyger and his team found

that one particular protein, called

TRPV1, facilitated gentamicin’s

entry into hair cells in the

presence of inflammation or

an immune response. Mice

bred without working TRPV

were protected from hearing

loss caused by gentamicin

(Science Advances, doi.org/c8jn).

Steyger hopes new techniques

that can identify microbes

more rapidly will mean doctors

may soon be less reliant on

broad-spectrum antibiotics

to treat newborns. RPS

frequency of less than 1kHz,

or 1000 times per second. In

contrast, Tee’s sensors send back

signals at 9Mhz, or 9 million

times per second.

The team designed different

types of sensors to better mirror

human touch. One responded to

quick, dynamic changes, another

to static forces, producing signals

that increased in frequency as

the force on it increased. A third

type sensed temperatures.

Tee and his colleagues then put

the skin onto a prosthetic hand

that grasped a hot cup of coffee

and found that all three types

of sensations were recorded

(Science Robotics, doi.org/c8jq).

“[This] has the potential to

greatly simplify and make it

possible for robots to have whole-

body skin, just like humans,” says

Tee. Another possible use of the

skin could be to cover prosthetic

limbs. This might one day help

people use them better, and

restore sensation to those who

have lost it. Ruby Prosser Scully

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