9:30 AM - 11:30 AM
▲ [9a-PA2-6] Development and characterization of biocompatible microbatteries for powering ingestible sensors
Keywords:Biocompatible, Microbattery, Ingestible sensor
Biocompatible batteries hold promise for many applications—electronic medical implants, health monitoring devices, and environmental sensors. One concrete example is ingestible sensors, that can be employed for regular monitoring of vital body functions such as core body temperature, controlled drug release, and for checking of medication adherence. Presently, ingestible sensors are usually powered by large batteries that contain toxic electrode materials. As a consequence, the whole system requires encapsulation to ensure safe use. Moreover, fabrication of the batteries is often based on conventional and therefore possess only limited potential for miniaturization. There have been examples of microfabricated batteries with smaller form factors, but the thin electrodes limit the operating times of the microbatteries to a few minutes. Here we present the development of biocompatible microbatteries that are realized by a combination of conventional microfabrication techniques and direct printing of the electrode materials using functional inks. The electrodes of the microbatteries with nominal footprints of 0.7 x 3.2 mm2 and consisting of Ag/AgCl cathodes and Zn anodes were fabricated by first depositing Au thin films as current collectors, using standard photolithography followed by metal sputtering. Both the Ag/AgCl and Zn electrodes were then formed by direct printing using a custom-made system. The microbatteries were characterized by galvanostatic testing in simulated gastric fluid at current levels ranging from 2 to 100 μA. It is anticipated that the presented approach for realizing biocompatible microbatteries can enable more complex battery architectures and also enable smaller footprints, thereby facilitating their integration in future sensor devices aimed at medical and environmental applications.