Scientists have created the world's smallest programmable robots, each smaller than a grain of salt and costing just one penny. Learn how this breakthrough could revolutionize medicine and manufacturing.
Scientists from the University of Pennsylvania and the University of Michigan have created the world's smallest programmable robots. These tiny machines are so small that they are nearly invisible to the human eye, yet they are capable of swimming, sensing their environment, making their own decisions, and operating continuously for months. Remarkably, each robot costs just one penny to make. The research was published in Science Robotics.
Tiny Breakthrough
Each robot is about 200 by 300 by 50 micrometres in size, making it smaller than a grain of salt. It is similar in size to many microscopic living organisms. Because of this, they might one day be used in medicine to monitor individual cells or in manufacturing to help build very small devices.
The robots are powered by light and contain small computers. They can be programmed to move in complex patterns, detect changes in temperature, and change direction accordingly. Unlike earlier microscopic machines, they do not rely on wires, magnets, or remote control. This makes them the first fully autonomous and programmable robots at such a tiny scale.
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According to Marc Miskin, one of the lead researchers, this development opens up a new size range for robotics. While electronic devices have become smaller over time, robots have had trouble shrinking in the same way. For decades, it was thought nearly impossible to build robots smaller than one millimetre that could function independently.
How They Swim
The challenge lies in physics. At human scale, gravity and momentum control movement. But at microscopic levels, forces such as drag and adhesion dominate. Moving through water at this scale is like moving through thick syrup. Traditional robot components, like legs or arms, do not work well when they are that small. They are hard to make and tend to break easily.
To address this, the researchers developed a completely new way for the robots to move. Instead of bending or paddling, the robots generate a small electrical field around them. This field gently pushes charged particles in the liquid, causing the surrounding water to move. As the water moves, it carries the robot along.
New Way Forward
The robot doesn't physically move its body. Instead, it causes the water around it to flow, almost like creating a tiny current. By adjusting the strength of the electrical field, the robots can swim in different directions, follow curved paths, and even move in groups, like fish swimming in a school.
Because there are no moving parts, the robots are very durable. They can be moved between samples using laboratory tools without being damaged. A small light source, such as an LED, is enough to power them which allows them to work for months.
Brains on Chips
For the robots to be truly independent, they also needed a "brain." Each robot includes a computer, sensors, control electronics, and miniature solar panels, all fitted onto a chip smaller than a millimetre. This challenge was tackled by a team at the University of Michigan, led by Professor David Blaauw, whose lab specializes in very small computers.
The biggest challenge was power. The tiny solar panels produce very little energy, much less than a smartwatch uses. To make the robots function, the team designed special electronic circuits that operate on extremely low power, reducing energy use by more than a thousand times.
Smart Movement
Space was another major challenge. Most of the robot's surface is covered by solar panels, leaving little room for the computer and memory. To solve this, the researchers simplified the computer instructions, allowing complex movements to be controlled with far fewer commands.
Thanks to these advancements, the robots can now sense, remember, and react. They can measure temperature changes with high accuracy and move toward warmer areas. Since temperature can indicate cellular activity, this could help scientists study the health of individual cells.
To share information, the robots perform tiny movements that act like a coded dance. Researchers record these movements through a microscope and decode the data, much like how scientists interpret the waggle dance of bees. Each robot can also be programmed individually using pulses of light.
Future Potential
The researchers say this is just the beginning. Future versions could move faster, store more complex instructions, use additional sensors, or operate in harsher conditions. By showing that intelligence, movement, and sensing can exist at such a tiny scale, this work marks a significant step forward.
As Miskin explains, once the basic building blocks are in place, many new possibilities emerge. These microscopic robots could shape the future of medicine, science, and manufacturing in ways that were once unimaginable.
