Robot stingray made of heart cells developed

Scientists have developed a tiny, light-controlled robot stingray that can swim with the help of muscle cells taken from rat hearts, an advance that could lead to more complex machines built from heart cells.
The findings may one day help scientists build entire living artificial hearts from muscle cells that would act more like natural hearts, the researchers said.
Containing about 200,000 rat heart-muscle cells, the robot measures 1.6 centimetres long and weighs ten grammes. The robot swims in a liquid that is loaded with sugar that serves as fuel, they said.
The robot's cells were genetically engineered to react to light. The researchers used pulses of light to steer the robot and control its speed.

Stingrays and related fish have flat bodies with long wing-like fins. Researchers, including Kit Parker from Harvard University, sought to build a robot that emulates the stingray's efficiency and manoeuvrability.
They began with gold skeletons that mimicked the shape of stingrays. These skeletons were then covered with a thin layer of stretchy plastic and a thicker body of silicone rubber.

Scientists placed muscle cells from rat hearts on the top of the robot. When stimulated with light, these cells contracted, pulling the fins downward, the 'Live Science' reported.
They designed the skeleton in a shape that stores some of the energy used to pull the fins down and releases it when the robot's cells relax, allowing the fins to rise.

The findings were published in the journal Science.