Sutures (surgical sutures) referring here to self-tying sutures.

"Shape-memory polymers -- materials that transform themselves into a pre-determined shape when activated -- will reach clinics beginning this year in the form of self-tying sutures, fast-adjusting orthodontic braces, and other devices. But these polymers require direct triggering by light or direct heat. Now Andreas Lendlein and colleagues have created shape-memory polymers that are triggered remotely by a magnetic field -- making it possible to activate them anywhere in the body."