Science & Tech · Science & Environment · 7 hrs ago
Algae-powered soft robotic arms move in response to light
Researchers at Delft University of Technology in the Netherlands built soft robotic arms coated with algae that move in response to light.
The algae photosynthesize in light and release carbon dioxide in darkness, changing the acidity around them.
That change makes one hydrogel layer swell or shrink, bending the arm against a second layer.
The arms are about three-quarters of an inch long and were tested in grippers that lifted a hollow metal sphere and a rubber ring.
The devices can grasp light objects, but the hydrogel takes several hours to bend significantly.
Unlike some other pH-responsive soft robots, they affect the surrounding liquid only locally, which may suit uses where limiting environmental impact matters.
The team has not named a specific application; its stated goal was to explore how living cells can work in functional materials.
Researchers at Delft University of Technology developed soft robotic arms with algae on their surfaces that bend in response to light.
The algae photosynthesize in light, changing the local pH and causing a hydrogel layer to swell; in darkness, the layer shrinks.
The arms are about three-quarters of an inch long and about as thick as a credit card.
A four-fingered gripper closed in light and lifted a hollow metal sphere, then released it when the light was turned off.
The chemical shift begins within seconds, but significant bending takes several hours.
- Who
- A research team at Delft University of Technology, led by Marie-Eve Aubin-Tam.
- What
- The team developed soft robotic arms coated with algae that move in response to light.
- When
- Wired published the article on 2026-11-09. The research date is not stated.
- Where
- Delft University of Technology in the Netherlands.
- Why
- The researchers aimed to explore what becomes possible when living cells are integrated into functional materials.
This story does not have two clearly opposing sides.
The research team constructed additional algal devices, including a four-fingered gripper and a hook-shaped gripper.
The algae began photosynthesizing, changing the local pH and causing the responsive hydrogel to swell.
The algae released carbon dioxide through respiration, and the hydrogel shrank.
- Research institution
- Delft University of Technology, Netherlands
- Arm size
- About three-quarters of an inch long and about as thick as a credit card
- Hydrogel response
- At pH 11, the responsive layer reached four times its original weight
- Light response
- Chemical shift began about 20 seconds after light was applied
- Dark response
- Chemical shift began about 10 seconds after it became dark
- Bending time
- Several hours for the hydrogel to bend significantly
What people are saying
We didn’t start with a specific application. Our goal has always been to bring the research of living materials to new levels
We wanted to explore what becomes possible when living cells are integrated into functional materials.
Microalgae are plantlike organisms that are largely self-sustaining