The fabrication of biocompatible sheets of tiny light-emitting diodes and photodetectors is reported online this week in Nature Materials. The sheets are stretchable and could in future be used for many applications, such as medical diagnostics within the body, or wearable light sources.

All conventional inorganic light-emitting diodes (LEDs) are brittle and cannot be stretched or conform to curved surfaces, which limits their potential uses. John Rogers and colleagues have now integrated tiny LEDs and photodetectors smaller than the tip of a pen on flexible, biocompatible electronic sheets. The sheets are stretchable and can be twisted by 720 degrees without losing functionality. Applications demonstrated include implantation under the skin of mice for possible diagnostic purposes and incorporation as light-emitters on surgical gloves.