Tiny Microbots to Jump Around Your Colon, Delivering Controlled Release Drugs

“When we apply a rotating external magnetic field to these robots, they rotate just like a car tire would to go over rough terrain,” said in a statement David Cappelleri, a Purdue associate professor of mechanical engineering. “The magnetic field also safely penetrates different types of mediums, which is important for using these robots in the human body.”

The researchers chose the colon as the testing ground for their new project as it is easy to enter and very messy.

“Moving a robot around the colon is like using the people-walker at an airport to get to a terminal faster. Not only is the floor moving, but also the people around you,” said Luis Solorio, an assistant professor in Purdue’s Weldon School of Biomedical Engineering.

“In the colon, you have all these fluids and materials that are following along the path, but the robot is moving in the opposite direction. It’s just not an easy voyage.”

The team conducted in vivo experiments in the colons of both mice and pigs under anesthesia. Pig colons are particularly similar to human ones.

They then used ultrasound to test in real-time how well the microrobot moved around and even tested the microrobot’s ability to carry and release a drug payload in a vial of saline. All these experiments proved very successful.

“We were able to get a nice, controlled release of the drug payload. This means that we could potentially steer the microrobot to a location in the body, leave it there, and then allow the drug to slowly come out. And because the microrobot has a polymer coating, the drug wouldn’t fall off before reaching a target location,” Solorio concluded.