It is now possible for a robot to move thanks to photosynthesis, although still on a small scale. Scientists in the Netherlands have created a two-centimeter robotic arm covered in live microalgae.
The prototype, developed at the Delft University of Technology, belongs to soft robotics: it uses deformable materials instead of the usual rigid joints. It is also biohybrid, because it combines artificial components with organisms that continue to carry out biological processes.
The arm has two layers of flexible gel. With light, algae carry out photosynthesis and alter the acidity of the material. One layer swells, the other barely changes, and the arm bends. In the dark, the algae release carbon dioxide and the movement is reversed.
The microalgae used belong to the species Chlamydomonas reinhardtii. Its activity modifies the chemical conditions of the environment and one of the sheets responds to these small chemical variations. When the illumination disappears, the microorganisms continue to breathe; Carbon dioxide contributes to changing the acidity again. Thus, the device can recover its shape without depending on a conventional electrical mechanism.
So you can grab and release small spheres or rings, without motors or batteries.
In demonstrations, a clamp held a small metal sphere and another design lifted a rubber ring. The demonstrations were carried out under controlled conditions and do not mean that the prototype can still perform complex tasks outside the laboratory.
Of course: the movements are slow; a wide push-up can take hours.
The initial reaction can be observed much earlier, but reaching a significant deformation takes considerably longer. That’s why the researchers accelerated some recordings up to 1,800 times. The work is a proof of concept that explores ways to harness natural processes to produce movement.
In the future, these materials could inspire devices that change shape with lighting.
REFERENCES
Fan Jiang, Friedrich Hans Kleiner, Roland Kieffer, Djanick de Jong, Jeong-Joo Oh and Marie-Eve Aubin-Tam. “Light-powered photosynthetic living actuator.” Nature CommunicationsOctober 22, 2026.
