Researchers present a futuristic-looking alternative to supplying energy to small implants: They have developed a fuel cell that can convert the body's blood sugar into usable electrical energy. This could be used to operate medical implants. The scientists were able to successfully illustrate this potential using the example of a system for insulin release for the treatment of type 1 diabetes in a mouse model. However, the scientists emphasize that the concept is still in an early development phase.
Small devices that are placed on or in the body are intended to help people with certain health problems: an example of this is the pacemaker, but other small medical devices and implants are already being used or are under development. One area of application is the treatment of type 1 diabetes, in which the body of those affected can no longer produce insulin. Insulin pumps are already used to deliver the hormone to regulate blood sugar levels.
Glucose fuel cell instead of battery
Of course, medical devices need a reliable power supply for their functions. Batteries or accumulators are usually used for this. However, for some time researchers have also been working on alternative ways of supplying energy, for example by using the movements of the body. A research team from the Swiss Federal Institute of Technology in Zurich (ETH) is now presenting a novel system. They use blood sugar - the body's fuel - to generate electrical energy: This energy carrier, called glucose, is found in the blood, but also in other body fluids. "So we came up with the idea of using excess metabolic energy to generate electricity to operate biomedical devices," says senior author Martin Fussenegger.
Their development involves a so-called fuel cell. This is the name given to technical devices that, instead of kinetic energy, can electrochemically convert a supplied fuel into electricity. In the case of the researchers' concept, this is the glucose from the body fluid. Its use is made possible by a specially developed anode (electrode) in the blood sugar fuel cell. It consists of copper-based nanoparticles and splits glucose into gluconic acid and a proton to generate electricity. The scientists explain that the positively charged particles can then set an electric circuit in motion.
In order to ensure the "fuel supply" and implantability of this fuel cell, it is coated with a biologically compatible algae product. This so-called alginate soaks up bodily fluid and allows glucose to pass from the tissue into the functional unit. The prototype of the blood sugar fuel cell developed so far resembles a small tea bag that can be inserted under the skin. The research group demonstrated that the concept can actually provide useful performance using a more sophisticated application that they had previously developed and successfully used in an experimental model of type 1 diabetes in mice.
Refined diabetes treatment
It is a system of specially manufactured beta cells in capsules that produce and release insulin when stimulated by electricity or LED light. The researchers' experiments on mice showed that the blood sugar fuel cell was now able to provide the necessary energy supply and a kind of sensor function. The system combines permanent power generation and controlled insulin release: As soon as the fuel cell registers a glucose excess, power production starts. The electrical energy is then used to stimulate the cells to produce insulin and release it into the blood. This then lowers the blood sugar level again. As soon as it falls below a certain threshold, the current and thus the insulin production stops. "The new system regulates the insulin level and thus the blood sugar level autonomously and could be used to treat diabetes in the future," says Fussenegger.
As ETH Zurich emphasizes in its press release, the concept is in an early development phase, despite the successful testing of the prototype in a mouse model. Industrial partners who have the appropriate means and know-how for further development are now in demand. "Because bringing such a device to market maturity far exceeds our financial and human resources," concludes Fussenegger.
Source: Swiss Federal Institute of Technology in Zurich, specialist article: Advanced Materials: doi: https://doi.org/10.1002/adma.202300890