21 October 2020
Self-powered glucose sensing
Published online 23 December 2019
A semiconducting polymer shows promise for implantable, self-powered biosensors.
Soon, implantable sensors might be able to provide continuous monitoring of blood glucose levels without the need for a clunky, rechargeable battery.
The chemistry to achieve this has been developed by a research team at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, with colleagues in the UK.
Scientists are working on developing implantable glucose-sensing devices that can provide continuous monitoring while avoiding the daily pain of pinprick testing. But their batteries can make implantation difficult and they need to be recharged or replaced. So research teams have been looking into ways to develop biosensors that can power themselves using the molecules present in the surrounding body fluids.
The KAUST team has developed a polymer material that can transport electrons along its backbone. They paired their material with the enzyme glucose oxidase. When placed in saliva, the enzyme on the material interacts with glucose, extracting electrons that are then transported by the KAUST polymer.
The research could lead to the miniaturisation of implantable biosensors and freedom from a need for external power sources.
"Working with the polymers was a lot of fun," says KAUST bioengineer Sahika Inal, explaining that small changes in chemical structure can produce polymers with completely different functions. But she adds that the fun was accompanied by some frustrations, because exploring all the possibilities took a lot of effort.
Further research could lead to biosensors self-powered using biological compounds other than glucose.
There is a significant research and development path to be pursued to move beyond the current proof-of-concept. But eventually the technology may be produced in a flexible form that could be attached to the skin’s surface. Further refinement could lead to devices suitable for longer term implants.
"My dream is to see these devices used for continuous monitoring of glucose levels inside living cells, helping us to understand the impact of glucose consumption on disease states," says Inal.
Bioelectronics specialist, George Malliaras of the University of Cambridge, UK, who was not involved in the study, comments: "A device that generates enough power from physiologically-relevant glucose concentrations to drive a transistor represents a significant step towards the development of autonomous implantable electronics."
Ohayon, D. et al. Biofuel powered glucose detection in bodily fluids with an n-type conjugated polymer. Nat. Mater. http://dx.doi.org/10.1038.s41563-019-0556-4 (2019).