For diabetics, monitoring blood sugar levels is an essential daily problem, usually involving finger tingling. The emerging alternative may be implantable devices that automatically monitor blood sugar levels and alert patients if they need attention, but powering these devices can be tricky. A new prototype glucose monitor has been designed to power itself with the same glucose in body fluids.
Powering implantable devices has long been a challenge. Durable batteries are the main method, but even if they are used for several years, surgery will eventually be performed to eventually replace them. Other teams have experimented with wearable devices that can charge implants wirelessly from in vitro, or disposable skin patches that monitor blood sugar without the need for extra power.
Researchers at King Abdullah University of Science and Technology (KAUST) have developed a new device that can absorb energy from the human environment. This not only eliminates charging issues, but also means that there is no need to put potentialtoxic substances used in batteries into the body. The new device is made entirely of biocompatible polymers that not only sense glucose, but also provide glucose. To do this, it is made up of an n-type semiconductor polymer coupled with an enzyme called glucose oxidase. When the enzyme reacts with the surrounding glucose, it extracts electrons from it and shuttles them through the connected polymer. This can be used to detect glucose levels in fluids such as saliva.
The same polymer also acts as an anode in a fuel cell. When coupled with a cathode made of another polymer, the chemical energy from glucose and oxygen is converted into electrical energy to run the device. Similar designs have required some kind of mesosome material to transfer electrons from enzymes to polymers, but these add to their own complexity. Fortunately, the new designs don’t need them at all.
David Ohayon, lead author of the study, said: “These media are usually toxic and need to be fixed to the electrode surface, which complicates the miniaturization of the device and shortens its service life. Our polymers seem to be able to carry enzymes in such a vicinity, resulting in effective electrical communication between the active center and the polymer main chain. “
The team says the system can operate at the concentration of glucose usually found in humans. It was also found to be stable enough to last more than 30 days. Researchers need to do more research to determine the usefulness of the idea. At present, this is a proof of concept.
Sahika Inal, lead researcher on the study, said: “This fuel cell is the first demonstration of a purely plastic-based, enzyme-based electrocatalytic electrocatalytic energy generation device operating in a physiologically related media. Glucose sensing and power generation are just two possible applications when synthetic polymers communicate effectively with catalytic enzyme-like glucose oxidase. Our main purpose is to demonstrate the general chemical methods and novel applications of this particular water-stabilized polymer class, which exhibits mixed conduction (ions and electrons). “
The study was published in the journal Nature Materials.