"4D" printed hydrogel can alter it's size
Engineers at Rutgers University have invented a method for "4D printing" a smart gel that could be used to provide structural rigidity in living organs, such as the lungs, and drug delivery. The hydrogel is able to change it's shape over time depending on the surrounding temperature. When temperatures are below 32°C (~89°F) the hydrogel absorbs water in the surrounding air and expands in size. Conversely, when the temperature increases above 32°C, it expels water and shrinks. The gel is printed using a lithography-based technique that 3D prints layers of a special resin, consisting of the hydrogel, a binder chemical, and a chemical that facilitates bonding. Check out the video below to see how the hyrdrogel works and read more about 4D printing at Rutgers University.