MIT engineers have created a biohybrid robot roughly the size of a stick of chewing gum and as thin as paper. A single layer of muscle cells, thinner than a strand of hair, contracts when exposed to light, making the device swim and change direction.
The prototype navigated a small watery maze and reached about four of its own body lengths per minute. The technology is at an early stage, but it could inspire mobile sensors able to explore fragile environments without disturbing them.

