Researchers create battery for edible robot pills

Robots that track your inner body’s functions may seem like science fiction, but Carnegie Mellon researchers are working to create electronically active, edible medical devices that can be implanted in a patient’s body. This development would essentially allow patients to ingest devices such as drug delivery systems or biosensors in pill form, and would be far less invasive than traditional methods of implantation. The device would move through one’s gastrointestinal (GI) tract like food. Christopher Bettinger, assistant professor of materials science and engineering and biomedical engineering, along with Jay Whitacre, professor of materials science and engineering, have completed the first step in the process by designing edible power sources for such devices.

The battery, designed with materials that are safe to consume, is also meant to be taken in pill form. “We have designed a battery that is made of simple, biocompatible materials that are consumed daily in common diets.... This is a platform technology that can serve as a power supply to drive active electronics on any edible medical device,” Bettinger said via email.

The devices are designed with flexible polymer electrodes and a sodium ion electrochemical cell, which allows the device to be folded into an edible pill that can be consumed by the patient. “The device is simply swallowed and follows the normal path of food through the GI tract,” Bettinger said. The battery’s power supply lasts roughly an hour, and the remnants pass through the patient’s system as waste within 18–24 hours. This method makes the battery economically efficient.
“This battery is designed for one-time use without recharging. The idea is to make them very cheap so that ingesting at one device per day would be economically feasible,” Bettinger said.

The development of this device is the beginning of an innovation in the way medical procedures are performed. “Making batteries that are able to power edible devices enables the integration of medical devices noninvasively for a variety of potential functions including sensors, drug delivery systems, etc.,” Bettinger said. “One example would be that we can perhaps have a system that can deliver large protein molecules to the body by programming their release in the small intestine. We haven’t done this yet, but it’s a potential application.”

While there are some technological hurdles to overcome, such as ensuring that the device is packaged well enough to withstand the acidic environment of the stomach, the team has ensured that the process is at least psychologically comfortable and biologically safe for patients. “We think there is a big future in edible devices because most patients are comfortable with swallowing a pill,” Bettinger said. Furthermore, the safe and biocompatible design of the device largely reduces the risk of any negative side effects as it passes through the GI tract.

The development of a safe, economically efficient power source has set the foundation to begin the development and widespread use of edible medical devices that perform targeted functions and offer treatments.

“The battery that we have developed is just the beginning. Once you have the battery technology down — which we do — this opens up a lot of different applications in actively powered edible electronics,” Bettinger said.

Bettinger and Whitacre believe that edible electronic devices will likely promote additional integration of the device with tissues and biological matter in the GI tract, according to their paper. Other applications of their edible pill may include monitoring the tissue of the GI tract, and even electrical stimulation of these tissues for treatment of digestion disorders.