MIT researchers designed and 3D-printed an array of soft, mechanical critters that are controlled by waving a magnet over them. The shapeshifters that fold up, crawl, grab things, and snap together into intricate formations may someday lead to new kinds of biomedical devices. For example, one of the devices "can even be directed to wrap itself around a small pill and carry it across a table." From MIT News:
"We think in biomedicine this technique will find promising applications," says (MIT mechanical engineer Xuanhe Zhao.) "For example, we could put a structure around a blood vessel to control the pumping of blood, or use a magnet to guide a device through the GI tract to take images, extract tissue samples, clear a blockage, or deliver certain drugs to a specific location. You can design, simulate, and then just print to achieve various functions."
In addition to a rippling ring, a self-squeezing tube, and a spider-like grabber, the team printed other complex structures, such as a set of "auxetic" structures that rapidly shrink or expand along two directions. Zhao and his colleagues also printed a ring embedded with electrical circuits and red and green LED lights. Depending on the orientation of an external magnetic field, the ring deforms to light up either red or green, in a programmed manner.