Scientists build micromotors smaller than human hair using laser light

Researchers at the University of Gothenburg have built laser-powered micro-gears smaller than a human hair. These micromotors could transform medicine, powering cell-sized machines, pumps, and valves inside the human body.

Imagine machines so small they could move inside a single human cell. That’s no longer science fiction — researchers at the University of Gothenburg have built light-powered micro-gears that could one day revolutionize medicine, nanotechnology, and chip design.

For decades, scientists have dreamed of shrinking engines down to microscopic size. Traditional gears stalled at about 0.1 millimeters — still too big to work at the scale of cells. But this new study breaks the barrier by swapping mechanical drive trains for laser light, unlocking a whole new way of thinking about microscale machines.

 How It Works: Gears Powered by Light

Instead of metal cogs and motors, the team used optical metamaterials — tiny, patterned structures that can trap and manipulate light.

Made from silica on a chip, each gear is just 16–20 micrometers in diameter (thinner than a strand of hair).

When hit with a laser, the gears spin. The laser’s intensity controls the speed, and simply changing the light’s polarization can even switch their direction.

These gears can pass on motion to other gears, convert rotation into back-and-forth motion, or even control tiny mirrors that redirect beams of light.

Lead researcher Gan Wang calls it a “fundamentally new way of thinking about mechanics at the microscale.” By letting light do the work, engineers no longer need bulky couplings or motors.

 Medical and Tech Breakthroughs Ahead

Because they’re about the size of a human cell, these micromotors could become tiny pumps or valves inside the body, regulating fluid flow or controlling drug release. Beyond medicine, they could also power lab-on-a-chip systems, sort microscopic particles, or even become part of future nanorobots.

Since light is easy to control and doesn’t require physical contact, these gears could scale into complex micro-machinery — all built directly onto a chip.

 Why This Matters

This discovery isn’t just about making small machines — it’s about rewriting the rules of mechanics. By using light as fuel, scientists may have finally unlocked the path to working engines at the scale of life itself.

As Wang explains, “We can now imagine machines that work at the level of cells — regulating flows, opening valves, or controlling light itself. The possibilities are endless.”