Implanted biomedical sensors could be powered by body glucose

Electronics that can monitor a person’s physiological and biochemical signals for disease but have no battery because they are powered by the patient’s own glucose have been developed by Washington State University.

Existing sensors for disease detection can be watches or patches which both have contact with the skin, but cannot be implanted, and they have batteries that need recharging. The Washington State University (WSU) researchers have created a biofuel cell that can produce the microwatts of power needed for implantable biomedical sensor electronics. The sensor electronics are also a new development and are described by the University as, “highly sensitive,” and, “state-of-the-art,” because of the very low power consumption. One use case for the sensor is replacing the need for finger-prick diabetes blood tests.

“The human body carries a lot of fuel in its bodily fluids through blood glucose or lactate around the skin and mouth,” said Subhanshu Gupta, an assistant professor in WSU’s school of electrical engineering and computer science which led the cross-disciplinary research team to develop the sensor. “Using a biofuel cell opens the door to using the body as potential fuel.”

(Left to right) Professor Su Ha and assstant professor Subhanshu Gupta examine a biofuel cell. Credit: Washington State University

According to WSU, the biofuel cell is non-toxic, unlike lithium batteries, it is biocompatible with the human body, and could power a sensor indefinitely by harvesting the host’s blood glucose. The biofuel cell consists of two cells stacked together and they use enzymes to generate the energy from the glucose, the body’s natural sugar supply. The two cells produce 0.5 Volts and can power the implant for 30 minutes before needing more glucose. Research is ongoing to improve how the biofuel cell works and how much power it produces. There is also a hybrid power alternative that has been proposed that uses a battery. The battery provides 1.6 micro Watts (µW) with a further 1.9 µW generated from the biofuel cells.

The sensor could be placed just under the skin where it could use the glucose that is naturally stored there by the human body. The researchers also state that the sensor could be manufactured cheaply through mass production. The sensor has been tested in the laboratory, so the next step is to test it in a body. Specifically, the WSU researchers want to have the sensor and its biofuel cell inside blood capillaries where it can use the blood glucose; but this will require the approval of medical regulatory authorities.

The biofuel cell and sensor electronics were created by a cross-disciplinary research team managed by WSU’s school of electrical engineering and computer science. The team involved WSU’s school of mechanical and materials engineering and the Gene and Linda Voiland school of chemical engineering and bioengineering. Former members of the University’s College of Nursing, which is now part of Walden University, also contributed. The WSU’s Grand Challenges seed grant funded the sensor’s development.

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