A variety of medical devices can be inserted into the gastrointestinal tract to treat, diagnose, or monitor GI disorders. Many of these have to be removed by endoscopic surgery once their job is done. However, MIT engineers have come up with a way to trigger such devices to break down inside the body when they’re exposed to light from an ingestible LED.

The new approach is based on a light-sensitive hydrogel that the researchers designed. Incorporating this material into medical devices could avoid many endoscopic procedures and would give doctors a faster, easier way to remove devices when they’re no longer needed or are not functioning properly, the researchers say.

“We are developing a set of systems that can reside in the gastrointestinal tract, and as part of that, we’re looking to develop different ways in which we can trigger the disassembly of devices in the GI tract without the requirement for a major procedure,” says Giovanni Traverso, an assistant professor of mechanical engineering, a gastroenterologist at Brigham and Women’s Hospital, and the senior author of the study.

In a study in pigs, the researchers showed that devices made with this light-sensitive hydrogel can be triggered to break down after being exposed to blue or ultraviolet light from a small LED.

Over the past several years, Traverso and Robert Langer, a David H. Koch Institute professor, have developed many ingestible devices designed to remain in the GI tract for extended periods of time. They have also worked on a variety of strategies to control the breakdown of such devices, including methods based on changes in pH or temperature as well as exposure to certain chemicals.

“Given our interests in developing systems that can reside for prolonged periods in the gastrointestinal tract, we continue to investigate a range of approaches to facilitate the removal of these systems in the setting of adverse reaction or when they are no longer needed,” Traverso says. “We’re really looking at different triggers and how they perform, and whether we can apply them to different settings.”

In this study, the researchers explored a light-based trigger, which they believed could offer some advantages over their earlier approaches. One potential advantage is that light can act at a distance and doesn’t need to come into direct contact with the material being broken down. Also, light normally does not penetrate the GI tract, so there is no chance of accidental triggering.

The research was funded by the National Institutes of Health, the Bill & Melinda Gates Foundation, the Koch Institute Support (core) Grant from the National Cancer Institute, and an AAAS L’Oréal USA for Women in Science Fellowship.