Batteries power most electric medical implants. Pacemakers, for example, use the same battery for years without recharging, but eventually have to be replaced once the charge starts to run out.
There have been numerous attempts to create technology to generate electricity from within the body to power these devices. These have resulted in rather modest voltage outputs, making these solutions impractical for use in medicine. Success in this field will mean that implants can stay in the body indefinitely, avoiding the dangers and costs associated with replacement surgeries.
Now, researchers from Sungkyunkwan University in Seoul, South Korea have developed a triboelectric generator and an ultrasound probe that work together to produce substantial amounts of electric current inside the body.
The ultrasound probe delivers vibrations toward the triboelectric generator, itself a thin sheet-like device that can be placed deep within the body. As it absorbs the ultrasound waves, the generator outputs an electric current that is substantial enough to power cardiac implants and other medical devices.
The generator only has to operate about once a day, depending on what it’s powering, to create enough electricity to charge an implant until the next time.
According to the researchers, a lithium-ion battery suspended in water was charged at 166 microcoulombs per second. The generator was able to produce 2.4 volts and 156 microamps when placed within pig tissue and resonated using an external ultrasound transducer.
Flashbacks: Body-Worn Electric Generator to Power Medical Implants, Wearable Devices; Cheap Electrochemical Diagnostic System Featuring a Triboelectric Generator; Skin Patch Generates Electricity to Energize Implants, Wearables
Study in journal Science: Transcutaneous ultrasound energy harvesting using capacitive triboelectric technology