As it stands, plants tend to flex and bend towards or away from a light source, and this is achieved by expanding cells on the side of the shoot that is farthest from the light. This particular process is known as phototropism, which proved to be the kick in the rear end that caused the Berkeley team to create a hydrogel which does the same. Such a light-responsive gel might prove useful in future applications which require flexible components, and it will include soft robotics, too.
Seung-Wuk Lee, the study’s primary researcher and an associate professor of bioengineering at Berkeley, said, “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. Because the gels shrank unevenly, the material bent when the light hit it.”