MIT’s Fuel Cell Technology Harvests Energy from Glucose
Researchers have developed a fuel cell that can convert glucose into electricity. The goal: powering medical implants from within.
Battery technology has advanced significantly since the first medical implants were introduced in the 1950s. The first cardiac pacemakers, for example, used nickel-cadmium and zinc-mercury batteries and only lasted a few years before they needed replacement. Modern pacemaker batteries, which use lithium iodide technology, offer a significant improvement with a lifespan of seven to eight years.
Timeline of how implant technology has developed alongside implantable power source development. Image used courtesy of Advanced Materials
But what if implants like pacemakers could derive power from the energy sources already present in the human body? Researchers at MIT and the Technical University of Munich have invented a glucose fuel cell that could make this a reality.
Glucose as a Source of Electrical Energy
Glucose is one of the most abundant energy sources found in nature. Leveraging the abundance of glucose in the human body, researchers at MIT and the Technical University of Munich (TUM) have invented an “ultrathin” glucose fuel cell that reacts with glucose in the human body to produce electricity. The device is 400-nm thick and can withstand temperatures up to 600°C, according to the researchers.
Ultrathin glucose fuel cell. Image courtesy of MIT
While glucose fuel cells are not a new technology, the key innovation in this new ultrathin glucose fuel cell is its power density.
High Power Density, Small Scale
With a power density of 43 microwatts per square centimeter, the cell proposed by MIT and TUM is said to have the highest power density of any existing glucose fuel cell design and can successfully power implantable devices.
The fuel cell has an anode, middle electrolyte, and cathode to convert glucose to electrical energy. First, the anode reacts with glucose present in bodily fluids to form gluconic acid. This releases protons and electrons, which are separated by the electrolyte. The electrons can then flow to the cathode and provide power to an external device.
Diagram of a glucose fuel cell. Image courtesy of Originalwana
The main challenge researchers encountered when developing this new fuel cell was finding a material that could scale down to an ultrathin dimension while still remaining durable. In other glucose fuel cells, the middle electrolyte part of the fuel cell is typically made of polymers. Polymers are carbon-based, lightweight materials that have a relatively low melting point.
Ceramics, on the other hand, are inorganic, non-metallic materials that are durable and have high melting points. In order to achieve the small scale and high temperature tolerance of the glucose fuel cell, the researchers used a ceramic material for the middle electrolyte instead of a polymer.
Benefits for Patients with Medical Implants
Due to the high power density and small scale of the glucose fuel cell, researchers believe this cell could provide significant benefits for patients with implants such as pacemakers. Were this technology to be commercialized, patients and providers would no longer need to be concerned with battery life, MIT and TUM researchers say. Additionally, the glucose fuel cell may increase the ease of implantation because of its small form factor and weight.