Using |
Imagine
if there were electronics able to prevent epileptic seizures before
they happen. Or electronics that could be placed on the surface of a
beating heart to monitor its functions. The problem is that such devices
are a tough fit. Body tissue is soft and pliable while conventional
circuits can be hard and brittle—at least until now.
“We’re
trying to bridge that gap, from silicon, wafer-based electronics to
biological, ’tissue-like’ electronics, to really blur the distinction
between electronics and the body,” says materials scientist John Rogers
at the University of Illinois Urbana-Champaign.
With
support from the National Science Foundation (NSF), he’s developing
elastic electronics. The innovation builds upon years of collaboration
between Rogers and Northwestern University engineer Yonggang Huang, who
had earlier partnered with Rogers to develop flexible electronics for
hemispherical camera sensors and other devices that conform to complex
shapes.
This
is circuitry with a real twist that’s able to monitor and deliver
electrical impulses into living tissue. Elastic electronics are made of
tiny, wavy silicon structures containing circuits that are thinner than a
human hair, and bend and stretch with the body. “As the skin moves and
deforms, the circuit can follow those deformations in a completely
noninvasive way,” says Rogers. He hopes elastic electronics will open a
door to a whole range of what he calls “bio-integrated” medical devices.
One
example is what Rogers calls, an “electronic sock”—in this case,
elastic electronics are wrapped around a model of a rabbit heart like a
stocking. “It’s designed to accommodate the motion of the heart but at
the same time keep active electronics into contact with the tissue,”
explains Rogers.
Using
animal models, Rogers has developed a version of the sock that can
inject current into the heart tissue to detect and stop certain forms of
arrhythmia.
Rogers
also demonstrates prototypes of a catheter that can be inserted through
the arteries and into the chambers of the heart to map electrical
activity and provide similar types of therapies.
He
believes that one day this technology will lead to devices like an
implantable circuit that diagnoses and perhaps even treats seizures by
injecting current into the brain.
The
device might detect differences in brainwave activity that occur just
before a seizure sets in, and could automatically counteract any
electrical abnormalities. Prototypes of the circuits are being tested
that can detect muscle movement, heart activity and brain waves just by
being placed on the surface of the skin like temporary tattoos. The
prototypes can detect the body’s electrical activity nearly as well as
conventional, rigid electrode devices in use currently.
Rogers
says their size could offer benefits in many important cases, such as
monitoring the health and wellness of premature babies. “They are such
tiny humans that this epidermal form of electronics could really be
valuable in the monitoring of these babies in a manner that is
completely noninvasive and mechanically ‘invisible’,” he points out.
