Smart Plastics

A plastic that can tie itselt into a knot shows promise as a surgical thread and in some medical implants. The plastic can be engineered to retain a memory of a specific shape and to transform itself into that shape when warmed to body temperature. A researcher at M-I-T also says that, in tests on rats, plastic inserted as a loose knot tied itself in a surgeon's knot around an artery. The researcher says the plastic can be made into forms that dissolve when a wound is healed, or stay as a long-term implant.