Glucose fuel cell on a silicon wafer, 64x64mm (via MIT & Sarpeshkar Lab)
Fuel cell technology has been used in everything from cars to phone charging, and it is progressing on to provide its unique power-generating capabilities in future brain-machine interfaces. What sets this fuel cell apart from the others is that it runs off of the human body’s own glucose (sugar) stores found in cerebrospinal fluid. However, this isn’t a new idea. Scientists from the 70s designed a glucose-based fuel cell to power pacemakers, but the technology was scrapped as they found lithium-ion batteries could supply more power than the cell could generate. This is no longer the case as advancements in technology allowed the team from MIT, led by associate professor Rahul Sarpeshkar, to design a fuel cell that generates enough efficient energy to power future implants. The team fabricated the fuel cell out of silicon and platinum in the same manner as any semiconductor chip, but instead of processing information like a CPU, the cell generates power through the use of a ‘platinum catalyst’ which strips the electrons from glucose much in the same fashion as the body’s own cells. While the power generated isn’t astronomical, it is none the less impressive at generating hundreds of microwatts.
The team used platinum not only for its ability to strip electrons from sugar but also impart because it’s much less likely to be rejected by the human body’s immune system as the cell is designed to use the cerebrospinal fluid that’s used to protect the brain from the skull which has virtually no red or white blood cells to attack it. The most interesting aspect of the design consists of using the same fabrication process as other silicon semiconductors. This allows for integration of any circuit-based implants to be used such as neural-controlled prosthetic limbs for persons with spine injuries or smaller more efficient pacemakers. Don’t expect to see this new fuel cell implant anytime soon. MIT states that the designed as a ‘proof of concept’ and still requires years of clinical trials starting with animal integration first before its used on humans.