De Vector

Chinese researchers develop hydrogel that keeps deforming

The material can change shape for weeks after a single pulse of light, but remains at the research stage.

Researchers at the Chinese Academy of Sciences have developed a hydrogel that can change shape for periods ranging from minutes to weeks after a single exposure to near-infrared light. The peer-reviewed study describes applications in soft electronics and an experiment with a brain electrode in a rat pup.

The researchers developed a chemical system they call STERS: spatiotemporally evolving reactive species. The system uses, among other things, gallium-based liquid metal particles, monomers and near-infrared light to allow chemical reactions to continue across time and space.

As a result, the structure of the gel does not change only immediately after a stimulus. According to the researchers, the reaction can continue for up to about four weeks after a single exposure to light. This allows the gel to take on patterns and shapes on different timescales, from minutes to weeks.

In one experiment, the researchers used microscopic patterns that gradually shrank. They reported that the changing patterns could steer stem cells towards bone-forming or neuron-like properties. This is a laboratory finding, not evidence that the technique is already suitable for treating patients.

The group also integrated the hydrogel into a soft interface with electrodes. That interface adapted to the growing outer surface of a rat pup’s brain and enabled long-term recording of brain activity. The experiment was conducted in animals; the results cannot be directly extrapolated to humans.

The research was published in the journal Matter and is therefore peer-reviewed. This means that the manuscript was assessed by fellow experts, not that all possible applications have already been independently replicated or are technically ready for commercial devices.

The research is particularly interesting because many shape-changing materials respond quickly to an external stimulus but do not continue changing independently afterwards. The Chinese researchers are instead trying to create a material in which the reaction itself evolves over time.

For applications in medical implants and smart devices, questions remain about safety, durability, energy use and controllability. It must also become clear whether the materials remain stable outside the laboratory and whether the reactions can be controlled precisely enough for everyday use.

The discovery is therefore a step in materials science, not a breakthrough for consumer devices. The most certain result is that the team demonstrated, in controlled experiments, a hydrogel with long-term shape evolution.

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