Credit: K. Hudson/M. Rosnach

A miniature robotic stingray powered by rat heart-muscle cells can swim in a physiological salt solution, guided by light.

Kit Parker at Harvard University in Cambridge, Massachusetts, and his collaborators created the 16-millimetre-long mock-up, weighing just 10 grams, by encasing a gold skeleton mimicking a stingray's shape in an elastic polymer (pictured). The stingray can be remotely controlled thanks to a light-activated muscle layer, made from genetically engineered rat cells, which responds to light-pulse frequency.

The artificial fish represents a step towards the development of adaptive robots with capabilities inspired by nature, the researchers say.

Science 353, 158–162 (2016)