With the aid of magnetic coupling, power can be transmitted wirelessly from a transmitter to a receiver module. The prototype with the transmitter can be attached to the belt. Credit: Fraunhofer IKTS

For
more than 50 years, pacemakers have set the rhythm for many hearts. The
engineering of microelectronic implants has since advanced by leaps and
bounds: they have become ever-smaller and more technologically
sophisticated. The trend is moving toward miniaturized, intelligent
systems that will take over therapeutic and diagnostic functions. For
example, in the future implantable sensors will measure glucose levels,
blood pressure or the oxygen saturation of tumorous tissue, transmitting
patient data via telemetry. Meanwhile, medication dosing systems and
infusion pumps will be able to deliver a targeted release of
pharmaceutical substances in the body, alleviating side effects in the
process.

   

Technology that can be worn on a belt

All
these solutions are composed of probes, actuators, signal processing
units and electronic controls—and therein lies the problem, too: they
must have a power supply. Batteries are usually ruled out because of
their limited durability—after all, implants stay inside the body for
years.

Currently,
radio wave-based (HF) and inductive systems are most commonly in use.
However, these exhibit differences in efficiency based on location,
position and movement and are also often limited in range. Soon, a new
power transfer system should circumvent the limitations of previous
methods. Researchers at the Fraunhofer Institute for Ceramic
Technologies and Systems IKTS in Hermsdorf succeeded in wirelessly
transmitting power from a portable transmitter module to a mobile
generator module—the receiver.

“The
cylindrical shaped transfer module is so small and compact that it can
be attached to a belt,” says Dr. Holger Lausch, scientist at IKTS. The
transmitter provides an electric current of over 100 mW and has a range
of about 50 cm. As a result, the receiver can be placed almost anywhere
in the body.

“With
our portable device, we can remotely supply power to implants,
medication dosing systems and other medical applications without
touching them—such as ingestible endoscopic capsules that migrate
through the gastrointestinal tract and transmit images of the body’s
inside to the outside,” says Lausch.

The
generator module can be traced any time—regardless of power
transfere—with respect to its position and location. So if the generator
is located inside a video endoscopy capsule, the images produced can be
assigned to specific intestinal regions. If it is placed inside a
dosing capsule, then the active ingredient in the medication can be
released in a targeted manner.

   

Energy can pass through all non-magnetic materials

How
does this new, already patented system work? In the transfer module, a
rotating magnet driven by an EC motor generates a magnetic rotary field.
A magnetic pellet in the receiver connects to the alternating exterior
magnetic field and as a result, is set in rotation itself. The
rotational movement is transformed into electricity, thus the power is
produced right in the generator module.

“With
magnetic coupling, power can be transported through all non-magnetic
materials, such as biological tissue, bones, organs, water, plastic or
even a variety of metals. Moreover, the magnetic field produced has no
harmful side effects on humans. It doesn’t even heat up tissue,” says
Lausch, highlighting the advantages of the system.

   

Because
the modules available as prototypes are scalable in terms of range,
size and performance capacity, they can be used for more than medical
technology applications. They can also supply power wirelessly to
hermetically sealed sensors—such as those inside walls or bridges. This
makes them suitable for use in mechanical engineering and plant
construction and in the construction industry. Other conceivable
applications include the charging of power storage units and activation
of electronic components.

   

Using
a hip implant as a demonstration tool, Lausch and his team will
demonstrate how their wireless power transmission system functions at
the Hannover Messe from April 23 (Hall 13, Booth C10). As used here, the
technology electrically stimulates the ball-and-socket joint to
stimulate the growth of cartilage and bone cells.

Source: Fraunhofer Institute