Photo: Marc Miskin/UPenn
Engineers from the University of Pennsylvania and the University of Michigan have developed the world’s smallest autonomous, programmable robot, tens of thousands of times smaller than previous models, according to ScienceAlert.
The micro-robot, measuring roughly 200 by 300 micrometers with a thickness of about 50 micrometers, is capable of moving independently in liquid, sensing its environment, and performing computations. Despite its tiny size, the device integrates a processor, memory, sensors, and a propulsion system—an unprecedented level of integration at this scale. Smaller than a grain of salt, the robot can even balance on a fingerprint ridge or appear tinier than a date stamped on a coin.
Powered by solar cells generating around 100 nanowatts, the robot can measure the liquid’s temperature and transmit data while performing short, dance-like movements reminiscent of honeybees.
“This is really just the first chapter,” said Mark Miskin, a nano-robotics engineer at the University of Pennsylvania. He explained that the team demonstrated it is possible to embed a “brain, sensor, and motor” into an almost invisible object capable of functioning for months, opening a new frontier in micro-robotics.
For over 20 years, the smallest autonomous robots were over a millimeter in size. Shrinking below that scale is challenging due to micro-scale physics, where viscosity and drag dominate inertia. “At this size, pushing through water is like pushing through resin,” Miskin explained.
The breakthrough was made possible by combining a microscopic computer from the University of Michigan with a novel propulsion system developed in Pennsylvania. The robot has no moving parts or limbs; it moves by generating an electric field that drives surrounding molecules. “It’s like the robot is in a flowing river, but it also makes the river move,” Miskin said.
David Blau, a computer scientist at the University of Michigan, noted that placing a computer on such a tiny platform required rethinking programming and semiconductor design. The development took five years.
The micro-robots can synchronize and move in swarms like schools of fish. They could potentially operate autonomously for months if continuously powered by LEDs. Researchers hope to expand memory capacity and programming complexity in the future, with potential applications in medicine, such as monitoring cell conditions.
