Self-powered implant to monitor blood sugar level

The painful finger-pricks that diabetics that often undergo to keep a tab on their fluctuating blood sugar levels can be a thing of past.

Now, a team of researchers, including a scientist from the Central Electrochemical Research Institute (CECRI) in Karaikudi, has created an electronic biosensor that can be implanted to continuously monitor glucose levels in diabetes patients.

The new device, reported by the scientists in the latest issue of Nature Materials journal this week, pairs an electron-transporting polymer with an enzyme that extracts electrons from its reaction with glucose in bodily fluids to power itself. Bodily fluids such as human saliva can not only power the device, but also give a count of blood sugar levels of the users.

The implantable glucose-sensing devices, currently in use need batteries that need to be either recharged or replaced eventually, making the implantation a complicated process.

Biosensors market

Globally, the market for biosensors that contribute immensely to healthcare industry is around $13 billion and is still growing at a rate of 9 to 12 per cent annually. Glucose biosensors account for nearly 85 per cent of this market.

“Quick, accurate and early detection of abnormalities in metabolism is of paramount importance to monitor, control and prevent many diseases, including diabetes,” said David Ohayon, a doctoral student at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia and the first author of the study in a statement. Equally contributed to the research were Georgios Nikiforidis, Ohayon’s postdoctoral colleague, and their advisor Sahika Inal at Biological and Environmental Science and Engineering Division at KAUST.

Tamilarasan Palanisamy, a scientist at CECRI, a Council of Scientific and Industrial Research lab, was a postdoctoral fellow at KAUST and a part of the team that developed the enzymatic fuel cell which powers the device.

Inal’s team which has been on the look-out for a better alternative to both finger-pricking devices and battery-operated implantable devices that need regular replacement, stumbled upon a polymer developed at another KAUST scientist, Lain McCulloch. The polymer that McCulloch’s team synthesised was an n-type semiconductor which can accept and transport electrons.

How the technology works

To make it work as a self-powered glucose sensor, the scientists coupled this polymer with an enzyme called glucose oxidase, which extracts electrons from its reaction with glucose. Subsequently, they demonstrated that this polymer material for a month to establish its stability.

“We have developed the technology and demonstrated its ability qualitatively and quantitatively,” said Tamilarasan. “ More importantly, the biofuel cell we developed is found to generate microwatt per square centimetre range electricity which is sufficient enough to operate the sensor,” said Tamilarasan, who joined CECRI in 2018.

“Glucose sensing and power generation are only two examples of the applications possible when a synthetic polymer communicates effectively with a catalytic enzyme-like glucose oxidase,” Inal said adding that the biofuel cell is the first demonstration of a completely plastic electrocatalytic energy generation device operating using bodily fluids.