Capsule-Sized Biobatteries Could Power Ingestible Cameras in Small Intestine

Tech companies have developed many devices that work outside the body, such as cell phones, smart watches, tablets and hundreds of others. Inside the body, though? That’s obviously trickier for several reasons, but power for a device is a big one. Now, a team of biobattery researchers think they have a solution for the hard-to-reach small intestine, which winds around the human gut for an average of 22 feet.

The solution developed by the researchers at Binghamton University (Binghamton, NY, USA) builds on earlier findings about utilizing bacteria to create low levels of electricity that can power sensors and Wi-Fi connections as part of the Internet of Things. Other options inside the small intestine are less viable: Traditional batteries are potentially harmful, wireless power transfer from outside the body is inefficient, temperature differences aren’t enough to harness thermal energy and intestinal movement is too slow for mechanical energy. Instead, the new biobatteries utilize microbial fuel cells with spore-forming Bacillus subtilis bacteria that remain inert until they reach the small intestine.

Some people might balk at ingesting bacteria, but our bodies are filled with nontoxic microbes that help with digestion and other functions. Although the research has just been published, the team is already looking ahead to improving the capsule-sized biobatteries. Once the fuel cell reaches the small intestine, it takes up to an hour to germinate completely - faster would be better. The cell generates around 100 microwatts per square centimeter of power density - enough for wireless transmission, but 10 times more would offer many more options for use. The batteries also would require animal and human testing as well as biocompatibility studies. THE team can foresee several uses that low-level microbial fuel cells could power, including biological and chemical sensors, drug-delivery systems and electrical stimulation devices.

“There are some regions in the small intestine that are not reachable, and that is why ingestible cameras have been developed to solve this issue,” said Professor Seokheun “Sean” Choi, a faculty member in the Department of Electrical and Computer Engineering at the Thomas J. Watson College of Engineering and Applied Science, who led the research team. “They can do many things, such as imaging and physical sensing, even drug delivery. The problem is power. So far, the electronics are using primary batteries that have a finite energy budget and cannot function for the long term.”

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