In recent years, scientists have been trying to develop implantable devices that make it easier for the patient and doctors — most devices currently require maintenance, usually to replace an expired battery, every seven to 10 years. Scientists, however, have now developed a biodegradable battery that, once out of power, can be absorbed by the body.
“This is really a major advance,” Jeffrey Borenstein, a biomedical engineer at Draper Laboratory, a research and development center in Massachusetts, told Nature. “Until recently, there has not been a lot of progress in this area.”
The device was created by researchers at the University of Illiinois, who, in January, developed a rechargeable nanoribbon that relied on the electromechanical interaction, piezoelectricity, to power a device. Essentially, the rechargeable “battery” converted the movement of organs into electricity devices could use. In 2012, they also developed the precursor to the current device — a number of biodegradable silicon chips capable of tracking temperature and mechanical strain, and then transmitting the readings to an outside device.
Those devices were relatively bulky though, and the researchers subsequently looked to smaller materials. The biodegradable metals they used included magnesium foil, iron, molybdenum, and tungsten, which conducted electricity with the help of a phosphate-buffered saline solution. These materials were then held within a biodegradable polymer called polyanhydride. The type of metal they used determined the amount of electricity produced, with some producing 2.4 milliamps of power. When they were done working, they simply dissolved, leaving nothing harmful behind. “Almost all of the key building blocks are now available,” materials scientists John Rogers, of the university, told Nature.
The device is promising for both medical applications — able to go far within the body, where there’s less space — as well as environmental, according to Borenstein who said that thousands of them could be spread across an oil spill as chemical sensors. Nevertheless, the device needs further application, as it’s currently only able to maintain power for a day.
Source: Yin L, Huang X, Rogers J, et al. Materials, Designs, and Operational Characteristics for Fully Biodegradable Primary Batteries. Advanced Materials. 2014.