Light-steered robot swims on living muscle cells, MIT shows

Thin gel fins coated with light-sensitive muscle push the device through water

By LineZotpaper

Published23 October 2026

Read Time3 min

Engineers at MIT have built a tiny swimming robot that propels itself with living muscle cells and is steered by flashes of light, a demonstration they say could point toward cheaper, self-healing robots for environments too fragile for conventional hardware. The device, described in the journal Advanced Functional Materials, uses two gel fins coated with light-sensitive muscle tissue to push itself through water.

A robot that runs on muscle

The robot is built around a flexible gel framework about the length and width of a stick of gum, shaped into two fins. Each fin carries a layer of living muscle cells thinner than a human hair, genetically modified to contract when exposed to light. By directing light onto either fin, and varying how often it flashes, the researchers can control the robot's speed and direction.

In experiments, the robot swam and turned through a simple underwater maze. At top speed it covered about four times its body length per minute, far slower than an Olympic swimmer, who can manage up to 65 body lengths per minute, but roughly comparable to a cow shark moving at leisure.

"It takes a lot of force to move through water versus air," said Ritu Raman, associate professor of mechanical engineering at MIT and a study author. "The robot's quite strong, given its size."

A thinner, cheaper approach

The study marks the first demonstration of a very thin, two-dimensional robot that travels from place to place using living muscle tissue. Most existing biohybrid robots rely on larger, three-dimensional structures of lab-grown skeletal muscle that require millions of cells to fabricate. Raman said thinner designs could be cheaper to build and move more efficiently.

"We believe that biohybrid robots powered by living muscle could one day perform delicate jobs like exploring environments too fragile or unpredictable for conventional hardware, because living tissue is soft, responsive to its surroundings, and can heal itself," she said.

Tuning the supporting gel

The new robot builds on an earlier achievement from Raman's laboratory: an artificial muscle disk inspired by the human iris, whose thin layer of living cells could stretch and compress in different directions when illuminated. For the swimming robot, the team found the soft gel used in that earlier work shrank under the force of contracting muscle, so they switched to gelatin methacrylate (GelMA), a material commonly used for growing biological tissue.

The engineers tested different gel formulations, stiffness levels and groove shapes. Square-profiled grooves aligned the cells best, helping them fuse into fibers that contract together, and stiffer gels produced stronger contractions. A gel film of roughly half a millimetre balanced sturdiness against weight, and repeated pulses of light were used to exercise and strengthen the tissue before assembly.

In the finished device, each fin acts as an independent muscle, so researchers could guide the robot through the maze by moving a light source by hand over a petri dish. The paper's first author is Maheera Bawa, who worked with Arielle Berman, Laura Schwendeman, Ferdows Afghah and Seanbiron Johnson.

Analysis

Why This Matters

The robot is the first very thin, two-dimensional device to move from place to place using living muscle, suggesting useful actuators can be built from a single layer of cells rather than bulky 3D tissue.
Thinner designs need far fewer cells, which could lower the manufacturing cost of biohybrid robots and improve their movement efficiency.
Because living tissue is soft, responsive and able to heal itself, muscle-powered robots could eventually work in environments where conventional hardware is too rigid or disruptive.

Background

Biohybrid robotics combines living cells with synthetic structures to make machines that exploit biological properties such as self-healing and sensitivity to their surroundings. Until now, most working biohybrid robots have used large, three-dimensional chunks of lab-grown skeletal muscle, which require millions of cells to produce. The MIT team's previous work showed that thin muscle layers could be grown in intricate patterns and made to move in multiple directions, but the movements were tiny, on the order of 100 microns. The new study tackles the harder problem of generating enough force to push a whole robot through water, and the result remains an early proof of concept: the device was tested in a petri dish and steered by a researcher moving a light source by hand.

Key Perspectives

The MIT research team: A single engineered layer of living muscle can generate enough force for locomotion, and thin designs should be cheaper and more efficient than the bulky muscle blocks used elsewhere. They see future uses in delicate, hard-to-reach environments, where self-healing soft tissue is a genuine advantage.

Biohybrid robotics researchers more broadly: The result is a useful step in replacing motors with living actuators, and the independent light control of each fin gives a simple way to steer. The field will judge the approach by whether it can be reproduced, scaled and moved out of the laboratory.

Skeptics: At roughly four body lengths per minute, the robot is far slower than conventional swimmers, and it still depends on an external operator with a light source. Whether thin-muscle designs can generate the force needed for real-world tasks remains to be shown.

What to Watch

Whether other laboratories adopt the gel and groove configurations described in the paper, a sign that the thin-muscle approach is reproducible.
Whether the next generation of the robot can move without an external light operator, for example by carrying its own illumination or sensing.
Whether the muscle layers can be made thicker or stacked to generate more force without sacrificing the efficiency of the thin design.

Sources

MIT scientists build a tiny robot that swims using living muscle cells · Latest Science News -- ScienceDaily

Checked

12 claims in this story checked against 1 source: 10 supported.

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SupportedThe light-steered robot swims using living muscle cells.Latest Science News -- ScienceDaily: “MIT engineers developed a soft robot that can flap through water in response to flashes of light.”
SupportedThe device uses two gel fins coated with light-sensitive muscle to move through water.Latest Science News -- ScienceDaily: “The gel forms two fins, each coated with a layer of muscle cells far thinner than a human hair. These cells have been genetically modified to contract when exposed to light.”
Partly supportedThe demonstration could point toward cheaper, self-healing robots for delicate environments.Latest Science News -- ScienceDaily: “thinner, less bulky designs such as the team's new bot could be cheaper to build and could move more efficiently. "We believe that biohybrid robots powered by living muscle could one day perform delicate jobs like exploring environments too fragile or unpredictable for conventional hardware, because living tissue is soft, responsive to its surroundings, and can heal itself."”
SupportedRitu Raman said, “It takes a lot of force to move through water versus air” and “The robot's quite strong, given its size.”Latest Science News -- ScienceDaily: “"It takes a lot of force to move through water versus air," says study author Ritu Raman, associate professor of mechanical engineering at MIT. "The robot's quite strong, given its size."”
SupportedAt top speed, the robot covered about four times its body length per minute.Latest Science News -- ScienceDaily: “At maximum speed, it covered approximately four times its body length per minute.”
SupportedAn Olympic swimmer can travel up to 65 body lengths per minute.Latest Science News -- ScienceDaily: “Although that is much slower than an Olympic swimmer, who can travel up to 65 body lengths per minute”
SupportedThe study is the first demonstration of a very thin, two-dimensional robot that moves using living muscle tissue.Latest Science News -- ScienceDaily: “The device represents the first demonstration of a very thin, two-dimensional robot that can move from place to place using living muscle tissue.”
Partly supportedMost existing biohybrid robots use larger 3D lab-grown muscle structures that require millions of cells.Latest Science News -- ScienceDaily: “Most existing biohybrid robots rely on relatively large, three-dimensional structures made from laboratory-grown skeletal muscle. Producing these structures typically requires millions of cells.”
SupportedRaman said, “We believe that biohybrid robots powered by living muscle could one day perform delicate jobs like exploring environments too fragile or unpredictable for conventional hardware, because living tissue is soft, responsive to its surroundings, and can heal itself.”Latest Science News -- ScienceDaily: “"We believe that biohybrid robots powered by living muscle could one day perform delicate jobs like exploring environments too fragile or unpredictable for conventional hardware, because living tissue is soft, responsive to its surroundings, and can heal itself."”
SupportedThe earlier gel shrank under contracting muscle, so the team switched to gelatin methacrylate (GelMA).Latest Science News -- ScienceDaily: “The earlier artificial iris had used fibrin, an exceptionally soft gel, as its underlying structure. However, the team found that fibrin could quickly shrink under the forces exerted by contracting muscle cells”
SupportedSquare-profiled grooves helped align muscle cells into fibers that contract together, and stiffer gels produced stronger contractions.Latest Science News -- ScienceDaily: “They discovered that muscle cells aligned more effectively inside square-shaped grooves. This alignment was important because muscle cells that grow in the same direction are more likely to merge into fibers. Those fibers can then form stronger muscle tissue that contracts in a coordinated way.”
SupportedMaheera Bawa was the paper’s first author, alongside Arielle Berman, Laura Schwendeman, Ferdows Afghah and Seanbiron Johnson.Latest Science News -- ScienceDaily: “The MIT research team also included first author Maheera Bawa, along with Arielle Berman, Laura Schwendeman, Ferdows Afghah, and Seanbiron Johnson.”