A robot smaller than a grain of salt has been created

Research teams from the University of Pennsylvania, together with colleagues from the University of Michigan, have developed an ultra-miniature programmable robot, considered the smallest in the world. Its dimensions are so small that it is virtually impossible to see the device without specialized optics. Nevertheless, this microrobot can move independently, recognize commands, and transmit data to scientists. The engineers’ achievement was reported in the scientific journal Science Robotics.

The robot measures only about 200 x 300 micrometers and is approximately 50 micrometers thick. Simply put, the robot is smaller than a typical grain of salt.

Despite its microscopic size, it houses fully functional electronic components: a processor, memory, temperature sensors, and miniature solar cells. These elements generate extremely low power—around 100 nanowatts—but this is sufficient for the device’s autonomous operation.

One of the key challenges for the creators was ensuring the robot’s movement in liquid. Due to its miniature size, the resistance of the medium is colossal—even water feels like a highly viscous substance.

A solution was found through the use of an electric field. This generates directed movement of molecules around the microrobot’s body, allowing it to literally “float” in the flow it creates. Essentially, the device moves as if it were in an artificially generated current.

Despite its tiny size, the robot is capable of recognizing loaded programs and performing actions without external control, such as recording the ambient temperature. Information is transmitted in an unusual way—through a series of movements reminiscent of a unique “dance,” similar to the signaling system of bees.

The microrobot can be powered for several months using light from external sources, such as LEDs, captured by its solar panels. In addition to working individually, such devices can interact with each other, synchronizing their movements and forming dynamic groups, similar to schools of fish or swarms of insects.

In the future, with increased memory capacity and equipped with more advanced sensors, such microrobots could be used in medicine. Scientists see them as potential “smart observers” within the human body, for monitoring cell health or targeted drug delivery.

As a reminder, the scientists presented a humanoid robot with six arms.

To be continued…