Researchers from the University of Illinois at Urbana-Champaign have created bio-compatible LED arrays that can bend, stretch, and even be implanted under the skin. While this might cause some people to immediately think “glowing tattoos!”, the arrays are actually intended for activating drugs, monitoring medical conditions, or performing other biomedical tasks within the body. Down the road, however, they could also be incorporated into consumer goods, robotics, or military/industrial applications.
Many groups have been trying to produce flexible electronic circuits, most of those incorporating new materials such as carbon nanotubes combined with silicon. The U Illinois arrays, by contrast, use the traditional semiconductor gallium arsenide (GaAs) and conventional metals for diodes and detectors.
Last year, by stamping GaAs-based components onto a plastic film, Prof. John Rogers and his team were able to create the array’s underlying circuit. Recently, they added coiled interconnecting metal wires and electronic components, to create a mesh-like grid of LEDs and photodetectors. That array was added to a pre-stretched sheet of rubber, which was then itself encapsulated inside another piece of rubber, this one being bio-compatible and transparent.
The resulting device can be twisted or stretched in any direction, with the electronics remaining unaffected after being repeatedly stretched by up to 75 percent. The coiled wires, which spring back and forth like a telephone cord, are the secret to its flexibility.
Rogers and his associates are now working on commercializing their biocompatible flexible LED array via their startup company, mc10.
The research was recently published in the journal Nature Materials.