A microscopic 'walker' just a few tens of micrometres in size can shuffle, rotate and even jump, powered only by light.

Hao Zeng and Diederik Wiersma at the University of Florence in Italy and their co-workers created their device using materials called liquid crystalline elastomers, which contract and expand like muscles. They added a light-sensitive dye, attached four cone-shaped legs made from acrylic resin and focused a laser beam on the robot. The device walked in a straight line on a patterned surface and even jumped up to 100 times its own body length.

Such a robot could be powered by ambient light alone, and could be modified to perform other actions such as swimming, the authors say.

Adv. Mater. http://doi.org/f2747b (2015)