Could Microscopic Robots Run Through Your Veins?

Four-legged robots, the width of a hair in size, can be powered by shooting lasers shooting into onboard solar cells.

antastic Voyage is a science fiction film from 1966. The movie involves a submarine crew. The characters have shrunk down to microscopic size and travel into the body of an injured scientist. Spoiler alert: The group ultimately repairs his brain by destroying a blood clot.

On a musical note, hip hop fans likely know Coolio’s song “Fantastic Voyage.” It has this catchy chorus:

“Slide, slide, slippity slide
With switches on the block in a ‘65
Come along and ride on a fantastic voyage
Slide, slide, who ride?”

He released the song in 1994, on the album “It Takes a Thief.”

Let’s re-enter the real world, one in which robots that are so small that we cannot see them with the naked eye. Microscopic robots or microbots are have arrived. What if we could inject them (through hypodermic needles) to travel through our veins and explore our bodies? The robots recently described in the journal Nature are about the width of a human hair — and have four legs powered by onboard solar cells.

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The nanobots recently described in the journal Nature are about the width of a human hair (wider than those depicted here!) Photo by Eric Krull on Unsplash

Motors to move robots challenging to build

Unfortunately, such devices are remarkably challenging to make at the micron scale. Creating small-scale motors, or actuators, that allow the robots to move is not easy. But the future is here: Today, we look at a new report of the creation of a new type of electronic actuator that is layered onto the circuit to drive it. More specifically, we look at an army of four-legged microscopic moving robots.

We begin with a problem: It is challenging to create the tiny engines that power a microbot’s movement. Fortunately, newer actuators take advantage of magnetism and other innovative approaches. Researchers then layer the actuator directly onto a controlling circuit.

In a recent study, scientists report building four-legged robots that are microscopic. The robots walk when a laser stimulates them. The microbots are small enough to be injectable into the body via hypodermic needles. How small? The robots are more miniature than 0.1 millimeters wide — around the width of a human hair — and have four legs powered by on-board solar cells.

It gets more interesting. The scientists fire laser light into the solar cells. This light triggers the robot’s legs (controlled by silicon electronics) to move, and the robot can walk. The walking robots are slower and less easy to manage than their swimming counterparts. Also, our ambulating microbots do not sense their environment. Still, the newer robots could someday explore biological realms.

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Photo by Mathew Schwartz on Unsplash

These robotic prototypes illustrate the possibility of integrating electronics with actuators, parts the enable device movement. Before there can be practical applications for the robots in the biomedical world, we optimally need to see microbots sense (and respond to) their environment. Could robots repair materials at a microscale?

The robots are scalable: Here’s how

The study authors produced the robot components in parallel. They could make over one million of them from a single four-inch silicon wafer. For robot legs, they used platinum only a single nanometer in thickness. When stimulated by laser light, this platinum bends, allowing for the slow walking motion of about one body length per minute.

Imagine if we added brains and a battery to these nanobots. Autonomous, mass-produced microbots to explore our bodies. Or repair materials at a microscopic scale. The future is coming quickly.


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I have degrees from Harvard, Yale, and Penn. I am a radiation oncologist in the Seattle area. You may find me regularly posting at

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