Implantable biofuel cells operating in vivo: Providing sustainable power for bioelectronic devices: From biofuel cells to cyborgs

Implantable devices harvesting energy from biological sources and based on electrochemical transducers are currently receiving high attention. The energy collected from the body can be utilized to activate various microelectronic devices. This article is an overview of the recent research activity in the area of enzyme-based biofuel cells implanted in biological tissue and operating in vivo. The electrical power extracted from the biological sources presents use for activating microelectronic devices for biomedical applications. While some microelectronic devices can work within a fairly broad range of electrical operating conditions, others, such as pacemakers, require precise voltage levels and voltage regulation for correct operation. Thus, certain classes of electronic devices powered by implantable energy sources will require careful attention not only to energy and power considerations, but also to voltage scaling and regulation. This requires appropriate interfacing between the energy harvesting device and the energy consuming microelectronic device. The paper focuses on the problems in the present technology as well as offers their potential solutions. Lastly, perspectives and future applications of the implanted biofuel cells are also discussed. The considered examples include a pacemaker and a wireless signal transfer system powered by implantable biofuel cell extracting electrical energy from biological sources.