Charging pacemaker batteries with ultrasound
Scientists from the South Korean Institute of Science and Technology (KIST) are working on a noninvasive battery recharging system for heart pacemakers, which is a more convenient alternative to surgical replacement once a pacemaker’s battery loses charge. KIST’s implantable ultrasound-powered generator utilises “triboelectric” materials – when rubbed together, these materials produce an electric charge.
In the case of this generator, externally applied ultrasonic waves cause thin layers of triboelectric and ferroelectric (iron-based) materials to vibrate back and forth between two electrode layers. This generates an electrical current, which could be used to charge a battery.
The first test was embedding the generator in pork to stimulate human flesh. In later tests, when the generator and an emitter were submerged underwater, located 6 cm (2.4 in) apart, some 8 milliwatts of charging power was produced. This charge was enough to simultaneously illuminate 200 LEDs, or transmit a Bluetooth signal underwater.
The system could also be utilised in undersea technologies.
The KIST scientists adopted ultrasonic waves as an energy transmission medium, instead of electromagnetic waves or magnetic fields which can produce too much heat or be easily disrupted. The safety of using ultrasonic waves in the human body has been guaranteed in various medical applications, such as organ or foetal condition diagnosis.
“This study demonstrated that electronic devices can be driven by wireless power charging via ultrasonic waves,” said KIST Lead scientist, Dr. Hyun-Cheol Song. “If the stability and efficiency of the device are further improved in the future, this technology can be applied to supply power wirelessly to implantable sensors or deep-sea sensors, in which replacing batteries is cumbersome.”
Scientists at Saudi Arabia’s King Abdullah University of Science and Technology have been working on an ultrasonic implant-charging system of their own, which incorporates a hydrogel that produces electricity when exposed to ultrasound. Other experimental methods of recharging pacemaker batteries without removing them include the use of light, heartbeats, and body movements.
Category: Features, Technology & Devices
