Binghamton University Scientists Develop Biobattery That Powers Ingestible Devices and Biosensors Inside the Human Small Intestine
Biobattery might one day power clinical laboratory testing devices designed to function in vivo to measure and wirelessly report certain biomarkers
Clinical laboratories may one day regularly process biomarker data sent by ingested medical devices from inside the human body, such as the colon and intestines. But powering such devices remains a challenge for developers. Now, researchers at Binghamton University in New York have developed a biobattery that derives its power based on pH reactions when it comes in contact with acids inside the gut.
The biobattery uses microbial fuel cells with spore-forming bacteria for power and it remains inactive until it reaches the small intestine.
Ingestible devices, such as wireless micro cameras, are being utilized more frequently to investigate a myriad of activities that occur in vivo. But traditional batteries that power ingestible diagnostic gadgets can be potentially harmful and are less reliable.
In addition, the small intestine in humans is typically between 10 and 18 feet in length and it folds several times to fit the abdomen. Thus, the inside area can be very difficult to reach for diagnostic purposes.
The scientists published their research in the journal Advanced Energy Materials titled, “A Biobattery Capsule for Ingestible Electronics in the Small Intestine: Biopower Production from Intestinal Fluids Activated Germination of Exoelectrogenic Bacterial Endospores.”
“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 Seokheun “Sean” Choi, PhD (above), Professor of Electrical and Computer Engineering at Binghamton University, in a news release. “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.” As these technologies develop, clinical laboratories may play a role in collecting biomarker data from these devices interpretation by physicians. (Photo copyright: Binghamton University/Jonathan Cohen.)
How Binghamton Researchers Developed Their Biobattery
To develop their new biobattery, the Binghamton researchers encased Bacillus subtilis, a bacterium found in the gastrointestinal tract of humans, in a graphene integrated hydrogel that excels at grabbing moisture from the air.
The dime-sized fuel cell assembly is then sealed with a piece of Kapton tape, which can withstand temperatures from -500 to 750 degrees Fahrenheit. When the tape is removed, moisture mixes with a chemical germinant that causes the bacteria to begin manufacturing spores.
“We use these spores as a dormant, storable biocatalyst,” explained Seokheun “Sean” Choi, PhD, Professor of Electrical and Computer Engineering at Thomas J. Watson College of Engineering and Applied Science, Binghamton University, in the news release. “The spores can be germinated when the nutrients are available, and they can resume vegetative life and generate the power.”
The biobattery generates around 100 microwatts per square centimeter of power density, but it can take up to an hour to germinate completely. After one hour, the energy generated from the device can power an LED light, a small clock, or a digital hygrometer, as well as a micro camera for in vivo use.
“We wanted to make these bio-batteries for portable, storable, and on-demand power generation capabilities,” Choi said in the news release.
“The problem is, how can we provide the long-term storage of bacteria until used? And if that is possible, then how would you provide on-demand battery activation for rapid and easy power generation? And how would you improve the power?” Choi added.
Heating the fuel cell decreased the time it took to reach full power to 20 minutes, and increasing the humidity resulted in higher electrical output.
Potential for Long-term Power Storage
In addition, after a week of being stored at room temperature, the activated battery had only lost 2% of its power. The researchers also believe that the device could function properly in an inactivate state for up to 100 years, provided there is enough moisture to activate the bacteria after the Kapton tape is removed.
“The overall objective is to develop a microbial fuel cell that can be stored for a relatively long period without degradation of bio-catalytic activity, and also can be rapidly activated by absorbing moisture from the air,” said Choi in the news release.
The federal Office of Naval Research funded the study.
More research and studies are needed to confirm the biobattery performs properly and is feasible for general use. This experimentation would require both animal and human testing, along with biocompatibility studies.
“I think this is a good start,” Choi added. “Hopefully, we can make a commercial product using these ideas.”
If the biobattery can power an ingestible medical device for a reasonable period of time, then this invention may be able to power a clinical laboratory testing device that could function in vivo to measure and wirelessly report certain biomarkers inside the body.