Inspired by phototropism, the phenomenon of plants growing toward light sources, bioengineers from the University of California Berkeley have created a hydrogel that can creatively be manipulated by light.
Researchers combined synthetic, elastic proteins with sheets of graphene. The graphene sheets generate heat when exposed to near infrared light. That heat affects the synthetic proteins, which absorb water when cooled and release it when hot.
“By combining these materials, we were able to mimic the way plant cells expand and shrink in response to light in a much more precisely controlled manner,” said principal inventigator Seung-Wuk Lee. “Because the gels shrank unevenly, the material bent when the light hit it. We used these bending motions to demonstrate a hand-shaped hydrogel that exhibited joint-like articulation when exposed to light.”
This research could have future applications in the emerging field of soft robotics, which takes a cue from squishy creatures in nature, like starfish, squids and octopuses, to create flexible components.
“Shape-changing gels such as ours could (also) have applications for drug delivery and tissue engineering,” said Lee.
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