Inspired by a parasitic worm that sticks its sharp teeth into its host’s intestines, Johns Hopkins researchers have designed small, star-shaped microdevices that can attach to the intestinal mucosa and release drugs into the body.
David Gracias, professor at the Johns Hopkins University School of Engineering, and Florin M. Selaru, a gastroenterologist and director of the Johns Hopkins Center for Inflammatory Bowel Disease, led a team of biomedical researchers and engineers who designed and tested the star microdevices.
Made of metal and a thin film that changes shape and covered with a heat-sensitive paraffin wax, “teragrippers”, each about the size of a speck of dust, can carry any medicine and can gradually release it into the body.
Innovation is really useful
The gradual or extended release of a drug is a frequently researched goal in medicine. Selaru explains that a problem with long-release drugs is that they often make their way through the gastrointestinal tract before they finish releasing their compounds.
“Normal constriction and relaxation of the gastrointestinal tract muscles make it impossible for long-acting drugs to stay in the gut long enough for the patient to receive the full dose,” says Selaru.
“We have worked to solve this problem by designing these small drug carriers that can attach autonomously to the intestinal mucosa and can maintain the drug load inside the gastrointestinal tract for the desired period of time.”
How does it work?
Thousands of robotic therapists can be deployed in the gastrointestinal tract. When the paraffin wax coating on the forceps reaches the temperature inside the body, the devices close autonomously and attach to the colon wall.
The closing action causes the small devices, with six corners, to stick into the mucosa and remain attached to the colon, where they are retained and gradually release their useful loads of drugs in the body.
Eventually, teragrippers lose control of the tissue and are released from the gut through normal gastrointestinal muscle function.
Gracias notes the progress made in the field of biomedical engineering in recent years.
“We have seen the introduction of dynamic, microfabricated smart devices that can be controlled by electrical or chemical signals,” he says. “But these mounts are so small that batteries, antennas and other components will not fit on them.”
Teragrippers, says Gracias, do not rely on electricity, wireless signals or external controls. “Instead, they function as small, compressed springs with temperature-triggered coverage on devices that autonomously release stored energy at body temperature.”