Japanese researchers have developed a material that can generate power after implantation by absorbing light from outside the body. The technology is being applied to the development of a battery-free cardiac pacemaker.
Currently, the lithium-ion batteries that power pacemakers need to be replaced every five to 10 years, requiring users to undergo postimplantation surgery. The thermo-electric generating material developed by Eijiro Miyako and fellow researchers at the National Institute of Advanced Industrial Science and Technology (AIST) would make this procedure unnecessary because it continuously generates power by converting light from outside the body into heat and, ultimately, electricity.
The material combines a bismuth alloy surrounded by a silicone resin with a carbon nanotube (CNT). When exposed to near-infrared laser light, the CNT generates heat that is converted into electricity by the bismuth alloy.
The smallest prototype made from the material thus far has a dice shape and measures 4 x 4 x 4.4 mm. The device has been implanted in a rat, where it produced up to 8 mV of electricity after being exposed to a near-infrared laser beam for 30 minutes. The temperature of the rat’s body surface rose to around 40°C.
Since approximately 200 mV of electricity are needed to get a pacemaker going, researchers are seeking to improve the material’s power generation efficiency by upgrading the nanostructure controller and laser illumination system. At the same time, they intend to conduct biocompatibility assessment and durability tests.
AIST is recruiting companies that are willing to collaborate and move the technology forward. The new material has other applications, including the fabrication of chest-mountable equipment to monitor cardiorespiratory functions, according to AIST.Miki Anzai