Researchers at the Georgia Institute of Technology and Korea University have developed a glucose-powered biofuel cell that uses electrodes from cotton that could potentially power implantable medical devices.

The fuel cell has twice as much power as traditional biofuel cells and could also be paired with batteries or super capacitors to create a hybrid power source for medical devices.

To make the biofuel cell, the researchers used gold nanoparticles that were assembled on the cotton to make high-conductivity electrodes. The method improves fuel cell efficiency and allows the researchers to connect the enzyme that oxidizes glucose with an electrode.

As the researchers stacked the gold nanoparticles layer-by-layer, they formed a gold electrode that would provide the electrocatalytic cathode and the conductive substrate for the anode. As a result, the layer-by-layer assembly boosted the power capacity by as much as 3.7 milliwatts per square centimeter.

“We could use this device as a continuous power source for converting chemical energy from glucose in the body to electrical energy,” Seung Woo Lee, an assistant professor in Georgia Tech’s Woodruff School of Mechanical Engineering, said in a press release. “The layer-by-layer deposition technique precisely controls deposition of both the gold nanoparticle and enzyme, dramatically increasing the power density of his fuel cell.”

The cotton’s porosity created an increase in the number of gold layers, unlike when using nylon fiber.

“Cotton has many pores that can support activity in electrochemical devices,” Yongmin Ko, one of the study’s co-authors, said. “The cotton fiber is hydrophilic, meaning the electrolyte easily wets the surface.”

Cotton fibers also improve biocompatibility of electrochemical devices because they are designed to operate at low temperatures for use in the body.

Implantable biofuel cells typically degrade over time, according to the researchers. But the cotton-based biofuel cell has improved long-term stability.

‘We have a record high power performance, and the lifetime should be improved for biomedical applications such as pacemakers,” Lee said.

Pacemakers and other implantable devices have batteries that are designed to last for several years, but oftentimes require surgery to maintain them or replace them entirely. The biofuel cell could give a continuous charge to the device batteries and extend the lifetime of the device without having to replace the battery, according to the researchers.

The researchers also suggest that the biofuel cell could be used to power devices that are designed for temporary use, such as devices that might be implanted for timed release of drugs.

The researchers plan to develop the biofuel cell further by testing it in an energy storage device and hope to develop it into a functional implantable power source.

This research was published in the journal Nature Communications and was supported by a National Research Foundation grant funded by the Korean Ministry of Science, ICT & Future Planning and the Basic Science Research Program through the National Research Foundation of Korea.