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No Batteries Required? Researchers Unveil Biological Supercapacitor That Powers Battery-Free Pacemakers With the Human Body
Technologies for medical implants continue to evolve at a fast pace. Pacemakers are one example of an implant that just keeps getting smaller. However, we still have to use traditional batteries to power them. This is why researchers have revealed a "biological supercapacitor" that uses the human body to power battery-free medical implants.
Pacemakers and Research Collaboration
The purpose of a pacemaker is to regulate abnormal heart rhythms. Modern models are about 6 to 8 millimeters thick and about the same width as a 50-cent coin. However, the battery occupies about half of the device. Batteries also contain toxic chemicals, so it's not ideal to put them inside the body. Furthermore, they run out of power periodically, requiring risky and painful replacement procedures.
To address these issues, research teams from the University of California, Los Angeles and the University of Connecticut collaborated to create a new bio-friendly storage system for energy. They call it the biological supercapacitor, which is harmless to the body and could extend the life of medical devices such as pacemakers.
How the Biological Supercapacitor Works
The biological supercapacitor that the researchers invented uses charged particles or ions from bodily fluids to produce power. More specifically, it uses the electrolytes from biological fluids such as urine and blood serum.
The supercapacitor also works with another device that the researchers call an energy harvester. This harvester converts bodily motion and heat into electricity. It works in a similar fashion as a self-winding watch that converts power from bodily movement. Then, the supercapacitor captures that electricity.
Supercapacitor Materials and Measurements
The research teams focused on making a custom supercapacitor that effectively captures energy and doesn't pose a risk to the human body. They used graphene, a carbon nanomaterial, to make the new device. Then, they layered it with modified human proteins to create an electrode, which is the conductor through which the device receives and sends electricity to and from the harvester.
The device is only 1 micrometer thick, which is much smaller than a human hair. This means that it could improve the energy efficiency of implantable devices. It can also maintain performance for longer than current pacemaker models. Additionally, it can twist and bend without being damaged and store more energy than the lithium film batteries that pacemakers currently use. Combining it with the energy harvester provides endless power and lifelong performance, explains UCLA postdoctoral researcher and study co-author Maher El-Kady.
Although the medical field isn't using supercapacitors yet, there's potential for their use in implants. They could even be developed for devices that stimulate the brain, speed bone growth and promote healing, says UCLA lead researcher and distinguished professor Richard Kaner. More research is needed before the technology can be used commercially.
Prior Research for Powering Medical Implants
This isn't the first time that researchers have looked at other ways to power implantable devices. In 2014, researchers at the Stanford University School of Engineering developed wireless charging devices. The technology allowed manufacturers to make medical implants as small as a grain of rice. They got the idea for the charging system from the technology that powers smartphones, electric toothbrushes and other small devices.