Army of a million microscopic robots created to explore on tiny scale

By Layal Liverpool

Criss Hohmann

An army of a million microscopic walking robots could enable scientific exploration on a tiny scale.

Researchers have developed microscopic robots before, but they weren’t able to move by themselves, says Marc Miskin at the University of Pennsylvania. That’s partly because of a lack of micrometre-scale actuators – components required for movement, such as for bending of a robot’s legs.

Miskin and his colleagues overcame this by developing a new type of actuator made of an extremely thin layer of platinum. Each robot uses four of these tiny actuators as legs, connected to solar cells on its back that enable the legs to bend in response to laser light and propel their square-shaped, metallic bodies forward.

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“Each solar cell is connected to a specific leg and by shooting the solar cells in sequence with a laser, you trigger the legs to contract to move in the way you want,” says Miskin. “It’s really cool.”

Using a process similar to that for creating circuit boards, the team were able to mass produce more than a million of the microrobots, each of which is smaller than a tenth of a millimetre – only visible under a microscope.

The robots are only able to walk around, but Miskin says they provide an important proof of concept, demonstrating that it is possible to develop and mass produce microrobots with on-board electronics. The next step will be to incorporate additional functions, he says.

“We’re developing things where we’ll have sensing capabilities, we’ll have programmability, stuff like that,” says Miskin. He also wants to develop microrobot swarms that work together. “There’s all sorts of cool stuff that happens when you wind up with a lot of [robots] working together versus just the individual.”

In the future, these bots could let us explore the world at a microscopic scale. They are small enough to be injected through a hypodermic needle and are made from biocompatible materials, so could potentially be developed to roam inside the human body. “The hope is that these robots are really going to take us into the micro world,” says Miskin.

Journal reference: Nature, DOI: 10.1038/s41586-020-2626-9