Harvard University’s Wyss Institute for Biologically Inspired Engineering has developed 4D printing – that is 3D printing which moves and grows.
They printed cellulose fiber flowers which contain acrylamide hydrogel which absorbs water. So, when the flowers are placed on water, the gel absorbs the water and the flowers move. Very cool video here:
As an article about the implications discusses, the medical applications include: smart textiles; autonomous robotics; biomedical devices; drug delivery; and tissue engineering.