A team of scientists at the Wyss Institute for Biologically Inspired Engineering at Harvard University and the Harvard John A. Paulson School of Engineering and Applied Sciences has evolved their microscale 3D printing technology to the fourth dimension, time. Inspired by natural structures like plants, which respond and change their form over time according to environmental stimuli, the team has unveiled 4D-printed hydrogel composite structures that change shape upon immersion in water.
Mimicking the variety of shape changes undergone by plant organs such as tendrils, leaves, and flowers in response to environmental stimuli like humidity and/or temperature, the 4D-printed hydrogel composites developed by Jennifer Lewis, Sc.D., senior author on the new study and her team are programmed to contain precise, localized swelling behaviours. Combined with a proprietary mathematical model developed by the team that predicts how a 4D object must be printed to achieve prescribed transformable shapes, the new method opens up many new and exciting potential applications for 4D printing technology including smart textiles, soft electronics, biomedical devices, and tissue engineering. This work was supported by funding from Army Research Office (ARO) and the National Science Foundation’s Materials Research Science and Engineering Center (MRSEC).