MIT Engineers Build Paper-Thin Swimming Robot Powered by Living Muscle Cells

The robot’s body is built from a gel sheet roughly half a millimeter thick, with fin-like extensions on each side. A single layer of living muscle cells—thinner than a human hair—coats each fin. These cells were genetically engineered to react to light. The gel film provides structural support while allowing flexibility, and the robot lacks a rigid internal skeleton.

In tests, researchers illuminated one fin at a time. The light triggered local muscle contraction, which bent the fin and propelled the robot through water. By switching illumination between sides, the team could steer the robot without physical tethers or onboard electronics. The muscle cells act as actuators, converting light energy into mechanical motion.

The fastest recorded speed was about four body lengths per minute. MIT says the work demonstrates how living actuators can power small, soft swimming robots. The approach combines synthetic materials with biological components, a strategy known as biohybrid robotics. Such light-controlled systems could inform future designs for agile, untethered devices in aquatic environments.