World’s smallest robots swim, sense heat, and think autonomously

Researchers at the University of Pennsylvania and the University of Michigan have developed the world’s smallest fully programmable, autonomous robots, each measuring about 0.2 by 0.3 by 0.05 millimeters—comparable in size to bacteria. These microscopic swimming robots can sense their environment, make decisions, and operate independently for months. They move by generating electric fields that push ions in the surrounding fluid, creating thrust without any moving parts. This innovative propulsion system enables durable, long-lasting operation in fluid environments, and the robots can also coordinate their movements in groups, similar to schools of fish. The robots’ intelligence is powered by ultra-miniaturized computers from the University of Michigan, which operate on just 75 nanowatts of power—about 100,000 times less than a smartwatch. Their surfaces are mostly covered by solar cells that harvest light for energy and serve as optical receivers for programming via light pulses. Each robot carries a unique identifier for individualized instructions. Equipped with temperature sensors sensitive