Glucose is the sugar we absorb from the foods we eat. It is the fuel that powers every cell in our bodies. Could glucose also power tomorrow’s medical implants? Engineers at MIT and the Technical University of Munich have designed a new type of glucose fuel cell that measures just 400 nanometres thick– this means it is thinner than a sheet of paper that is about 100,000 nanometres thick. The researchers envision that this cell could be used to power medical implants and sensors in the human body, without batteries or other energy storage devices.
The new device is also resilient, able to withstand temperatures up to 600 degrees Celsius. If incorporated into a medical implant, the fuel cell could remain stable through the high-temperature sterilization process required for all implantable devices. The heart of the new device is made from ceramic, a material that retains its electrochemical properties even at high temperatures and miniature scales. The researchers envision the new design could be made into ultrathin films or coatings and wrapped around implants to passively power electronics, using the body’s abundant glucose supply.
lucose fuel cells were first introduced in the 1960s, but the early models were based on soft polymers. These early fuel sources were replaced by lithium-iodide batteries. But glucose fuel cells at the time were based on soft polymers and were quickly eclipsed by lithium-iodide batteries, which would become the standard power source for medical implants, most notably the cardiac pacemaker. However, batteries have a limit to how small they can be made, as their design requires the physical capacity to store energy.
According to the research article, power requirements for implantable sensor-like devices typically vary from 100 nW to 1mW, which means such fuel cells can potentially power them. But for more power-hungry devices like pacemakers, there might be a requirement for multiple fuel cells to be implanted to generate enough power.