The University of Pennsylvania and University of Michigan teams have built a sub-millimeter microrobot that combines a processor, sensors and a propulsion system on a chip-like platform described in Science Robotics. The device — made of silicon, platinum and titanium and sealed in a glass-like layer — uses tiny solar cells to power an onboard computer and electrodes that create local fluid flows so the robot can swim. While the processor is much slower than a laptop, it can sense and respond to environmental cues and exchange messages with human operators; the next big goal is enabling microrobot-to-microrobot communication. The design is experimental and not yet suitable for use inside people, though researchers anticipate practical applications may appear within about ten years.
Microrobot Smaller Than a Grain of Salt Can Sense, Compute and Swim — A Step Toward Medical Microdevices
Researchers at the University of Pennsylvania and the University of Michigan have developed a sub-millimeter microrobot that integrates a processor, sensors and a propulsion system into a device smaller than a grain of salt, according to a paper published in Science Robotics and reporting by The Washington Post.
What It Is: The chip-like device is fabricated from familiar materials such as silicon, platinum and titanium and is encapsulated in a glass-like layer that protects the electronics from fluids. Tiny solar cells power an onboard computer and a pair of electrodes that generate local fluid flows to propel the robot — in short, it can swim.
Sensing and Computing: Although the robot’s processor runs at less than one-thousandth the speed of a modern laptop, the team reports it is sufficient for basic sensing and decision-making, such as responding to temperature changes. The researchers describe the device as able to "sense, think and act," a milestone for microrobotics.
Communication: The robot is designed to exchange information with human operators: operators can send commands to the device and receive status updates about what the robot senses and does. The authors identify inter-microrobot communication as the next major milestone — enabling multiple microrobots to coordinate would be a major advance.
Limitations and Outlook
The team emphasizes the system is highly experimental and not yet suitable for use inside humans. For example, the present design depends on tiny solar cells for power, which require light and therefore limit current in vivo applications unless alternative power or delivery strategies are developed. Still, coauthor David Blaauw of the University of Michigan told The Washington Post he would not be surprised if practical applications emerge within roughly a decade.
“Every living thing is basically a giant composite of 100-micron robots,” coauthor Marc Miskin of UPenn said, highlighting why working at this scale may open access to biological systems’ fundamental units.
Why It Matters: A microrobot that can move, process local information and communicate could one day underpin minimally invasive medical tools for tasks such as targeted drug delivery, navigating hard-to-reach anatomy, or microscale repair. The current study demonstrates a functional platform, and subsequent work will address power, reliability, coordination between devices and safety for medical use.
