Electronics: These bots were made for walkin’

The creation of an army of walking, microscopic four-legged robots is described in Nature this week. This achievement is the result of the development of a new class of actuator (a component that makes the robots move) that is compatible with existing silicon electronics.

Miniaturization of electronics to produce cell-sized robots has been a sought-after goal, but the technology has been limited by the lack of suitable micrometre-scale actuator systems. Marc Miskin and colleagues demonstrate a new class of electrochemical actuators that overcome this issue. These actuators form the legs of robots that are less than 0.1 mm in size (around the width of a human hair) and bend when stimulated by laser light, causing a walking motion. The authors produce over one million walking robots on a 4-inch wafer of silicon. The robots are powered by on-board silicon photovoltaics.

The authors suggest that these are the first known robots smaller than 0.1 mm in size in which on-board electronics are used to control actuation. They are robust, surviving highly acidic environments and temperature variations of more than 200 degrees Kelvin, and can be injected through hypodermic needles, offering the potential to explore biological environments. These robots currently have limited function; they are slower than other swimming robots, they do not sense their environments, and they lack integrated control. However, the authors conclude that their compatibility with existing silicon technologies should enable the development of increased capabilities.