The replacement of batteries for implantable medical equipment is a troublesome process, which requires an extraction through surgeries that would enhance risks of infection for patients. Fortunately, US and German scientists have recently developed a micro biofuel cell that facilitates prolonged operation for medical equipment through the self-sufficient “fuel” inside human bodies.
Implantable medical equipment such as pacemaker run for several decades, which is why the battery capacity is put to the test since these equipment cannot be plugged with cables for power supply or charging. Will it be possible to configure batteries with implantable medical equipment that generate power from blood sugar, sweat, or body fluid of human bodies?
Many related biofuel cells in the past, including glucose fuel cells that have been under development for several decades, were able to convert the chemical energy of blood sugar to electrical energy. Now MIT and the Technical University of Munich have developed a new battery by utilizing past experience and improving past battery designs.
The new fuel cell has a largely identical structure to existing fuel cells, which is formed with anodes and cathodes, as well as electrolytes. Anode would react with glucose within the human body and produce gluconic acid, with two protons and two electrons released from the process, where the electrons are collected within the circuit that would provide power for the implantable medical equipment, after electrolytes take away the protons and combine with the air that yields harmless water molecules.
The electrolytes of past glucose fuel cells were primarily made with polymers, though for this particular study, researchers managed to create a sturdy and stable ceramic through cerium (IV) oxide and new materials , and adopted platinum that is the same with that of hydrogen fuel cells for the electrode, with ceramic being able to effectively transmit protons, while platinum has a strong reaction similar to glucose.
The final battery that measures at roughly 300µm in width and 400nm in thickness has a pretty excellent power generation performance, despite its miniature dimension. To test the power generation, researchers created 150 fuel cells on a piece of wafer, before adding a glucose solution, which yielded a peak voltage of approximately 80MV that is an equivalent of 43µW/cm2.
The research team commented this is the glucose fuel cell that has the highest power density so far, and is enough to provide power for implantable equipment. Apart from a high production volume, ceramic materials are also able to prolong lifespan and sustain high-temperature sterilization before implants. Researchers believe that these fuel cells can also be made into thin film coating that wrap around the equipment for power supply purposes.
(Cover photo source: MIT)