properties such as resistance
Nanotechnology at your fingertips (Image: John Rogers/University of Illinois at Urbana-Champaign)
OUR fingers are precision instruments, but there are
plenty of things they are not sensitive enough to detect. Now we can
augment their talents – using wearable electronic fingertips that
provide tingling feedback about whatever we touch.
John Rogers
of the University of Illinois at Urbana-Champaign and colleagues have
designed a flexible circuit that can be worn over the fingertips. It
contains layers of gold
electrodes just a few hundred nanometres thick, sandwiched between
layers of polyimide plastic to form a "nanomembrane". This is mounted on
a finger-shaped tube of silicone rubber, allowing one side of the
circuit to be in direct contact with the fingertips. On the other side,
sensors can be added to measure pressure, temperature or electrical
electrodes just a few hundred nanometres thick, sandwiched between
layers of polyimide plastic to form a "nanomembrane". This is mounted on
a finger-shaped tube of silicone rubber, allowing one side of the
circuit to be in direct contact with the fingertips. On the other side,
sensors can be added to measure pressure, temperature or electrical
People wearing the device receive
electrotactile stimulation – a tingling sensation caused by a small
voltage applied to the skin. The size of the voltage is controlled by
the sensor and varies depending on the properties of the object being
touched.
Surgical gloves are one potential
application. Rogers, who worked with colleagues at Northwestern
University in Evanston, Illinois, and Dalian University of Technology in
China, says gloves fitted with the nanomembrane could sense the
thickness or composition of tissue via its electrical properties. A
surgeon could also whittle away at the tissue using a high-frequency
alternating current supplied by a battery attached at the wrist and
delivered via the nanomembrane itself, says Rogers.
Fiorenzo Omenetto at Tufts University in
Medford, Massachusetts, is impressed. "The work sets the stage for a new
generation of devices," he says.
There are applications beyond surgery, too. MC10,
the company commercialising the technology, is running animal trials of
a nanomembrane "sock" that can be wrapped around the heart. This
provides a 3D map of its electrical activity, useful in treating
irregular heartbeat.
MC10 is also working
with medical device company Medronic to use the membrane inside the
heart, sending it in on a limp balloon, which is then inflated to push
the membrane onto the heart's interior walls.
Rogers says MC10 is also collaborating
with sportswear firm Reebok on a product to be launched by the end of
this year. The aim is to build a "body-worn piece of electronics"
designed for contact sports, although Rogers declined to say exactly how
it will be used.
