Miniature robot swims with living muscle

Researchers have created a tiny swimming robot that uses living muscle tissue to move through water. The robot's flexible gel body is covered with a thin layer of muscle cells, which contract when exposed to light, propelling it forward.

Light triggers muscle contractions

The robot's movement is controlled by light, which activates the muscle cells to contract. These contractions cause the robot to swim, with its maximum speed being about four times its body length per minute.

Biohybrid robots gain attention

Biohybrid robots, which combine living tissue with artificial materials, are becoming more popular in robotics research. They offer potential advantages over traditional robots, such as flexibility, reactivity, and the ability to self-repair under certain conditions.

Cost-effective muscle design

Most current biohybrid robots use bulky structures made of many muscle cells, which are expensive to produce. MIT researchers have proposed a cheaper alternative using a thin layer of muscle cells, as described in a study published in Advanced Functional Materials.

Inspired by the human iris

The robot’s design was inspired by earlier work on a synthetic muscle disk modeled after the human iris. This disk had grooves where muscle cells were placed, allowing them to contract in different directions when exposed to light.

GelMA improves muscle performance

To enhance the robot's movement, researchers used a gel made of gelatin methacrylate (GelMA), a common material in tissue engineering. This gel helped align the muscle cells and allowed for stronger contractions, even when the gel was only half a millimeter thick.

Two fins, light-controlled movement

The robot has two fins made of muscle cells on either side of its body. These fins can be individually activated with light, allowing precise control of the robot’s direction. Light was manually directed at the fins to cause their contraction during testing.

Robot swims through a maze

In tests, the robot successfully swam through a simplified underwater maze. While its speed was much slower than that of an Olympic swimmer, it was comparable to the slow, steady movement of a nurse shark, according to MIT.

Future improvements planned

The researchers aim to improve the robot’s speed and efficiency. Even at its current pace, the robot could be useful for tasks like monitoring aquatic environments. Ritu Raman, a co-author of the study, highlights the potential of the robot’s design for future applications.