Shape-shifting polymers could one day be used in implantable electronic sensors that conform to tissue inside the body.

Credit: Takao Someya and Walter Voit

A team led by Takao Someya at the University of Tokyo attached organic thin-film transistors to polymers that deform when warmed. They first fabricated the device in the shape of a helix and then flattened it. When they applied heat, the device wrapped itself around a thin cylinder (pictured). Under the skin of a rat, the film softened to follow the contours of the tissue 24 hours after implantation, while still maintaining its electronic properties.

The authors say that their system offers advantages over other materials: stiff substances cannot move with the body and elastic materials are difficult to insert in vivo and hard to produce in bulk.

Adv. Mater. http://doi.org/sg7 (2014)