professor has developed solar-powered artificial skin, capable of detecting chemical and biological
molecules, that could be used to diagnose patients.
"With artificial skin, we can basically incorporate any function
we desire," said Zhenan Bao, a professor of chemical engineering, at the
American Association for the Advancement of Science on 20 February.
"That is why I call our skin 'super skin'. It is much more than
what we think of as normal skin."
Bao said that the skin,
which is being developed for use in robotics and prosthetic limbs,
could lead to the creation of diagnostic robots that detect disease
simply by touching a patient's blood or urine and registering the
levels of certain molecules. They could even monitor blood-alcohol
levels in drunk drivers by touching a subject's sweat.
The flexible polymer "skin" is coated with a layer of molecules
(precisely which molecule changes according to what researchers are
trying to detect) just a nanometre thick. On contact with certain
chemical or biological molecules, this layer binds itself to the
substance, thus signifying the detection.
"For any particular disease, there are usually one or more
specific proteins associated with it -- called biomarkers --
that are akin to a 'smoking gun'," said Bao. "Detecting those
protein biomarkers will allow us to diagnose the disease." The
theory was put into practice and Bao's team managed to correctly
identify a type of DNA.
The addition of a solar cell that can generate, conduct and
transmit signals from the sensors even when stretched to 30 percent
its length allows for far more mobility -- without a battery that
needs recharging, the subject can be lighter and have more freedom.
It's able to do this by working on two axes, with a wave-like
surface that conducts energy through a liquid metal.
The durable nature of these solar cells affords infinite
possibilities. They can not only be used on joints, as with
artificial skin, but can be adapted to clothing, cars, lenses and
even parts of buildings, said Darren Lipomi, a postdoctoral fellow
on Bao's team.
Bao was already well on her way to developing what she calls
"super skin", having invented an integrated sensor in 2010 that is
to touch and light pressure.
Touch sensitivity was introduced by adding a very thin layer of
rubber to the skin's surface. The rubber is made up of millions of
tiny inverted pyramids which alter thickness when touched,
affecting the flow of electricity through the skin. This change in
energy flow is interpreted by sensors as touch. The skin can be
made more sensitive by increasing the number of pyramids.