Scientists have developed a new energy storage device that works with fluids in the human body and could lead to more durable and battery-free pacemakers and other implantable medical devices. The bio-friendly energy storage system called biological supercapacitor is powered by charged particles, or ions, from body fluids like blood serum and urine. Pacemakers - which help regulate abnormal heart rhythms - and other implantable devices have saved countless lives.
However, they are powered by traditional batteries that eventually run out of power and need to be replaced, meaning another painful surgery and the risk of infection that accompanies it. In addition, batteries contain toxic materials that could endanger the patient if they spread.
The supercapacitor has invented loads using electrolytes from biological fluids such as blood serum and urine, and it would work with another device called energy harvesting. It converts heat and movement of the human body into electricity - in the same way that self-winding watches are powered by the movements of the user's body. Electricity is then captured by the supercapacitor.
Now, researchers at the University of California, Los Angeles (UCLA) and the University of Connecticut in the United States propose to store energy in these devices without batteries.
"The combination of energy harvesters with supercapacitors can provide endless power for lifetime implantable devices that can never be replaced," said Maher El-Kady, a UCLA postdoctoral researcher.
Modern pacemakers are generally about 6 to 8 millimeters thick, and about the same diameter as a 50-cent coin; About half of this space is usually occupied by the battery. The new super-capacitor is only 1 micrometre thick – much smaller than the thickness of a human hair – meaning that it could improve implantable devices’ energy efficiency.
The new biosupercapacitor includes a carbon nanomaterial called graphene laminated with human proteins modified as an electrode, a conductor through which electricity from the energy harvest can enter or leave. The new platform could also eventually be used to develop next-generation implantable devices to accelerate bone growth, promote healing or stimulate the brain, "said Richard Kane of UCLA, who led the study published in the journal Advanced Energy Materials.
