Next generation tattoos are implantable LEDs

Researchers in the US, China, Korea and Singapore have collaborated to develop flexible ultra-thin sheets of inorganic light emitting diodes (LEDs) and photodetectors for implantation under the skin for medical monitoring, activating photo-sensitive drugs, and other biomedical applications.


The PDMS substrate is flexible enough that the circuits can still function even if twisted or stretched by even as much as 75 percent. Rogers said most research has concentrated on organic LEDs (OLEDs), which are extremely sensitive to water and oxygen, but the flexible arrays are encapsulated in a thin layer of silicon rubber, which makes them waterproof and allows them to function well when implanted or completely immersed in biofluids. The design also eliminates the mechanical constraints normally imposed on such devices by the inflexible semiconductor wafers that support them.

The researchers successfully tested the LEDs by integrating a sheet into the fingertip of a vinyl glove, which they then immersed in soapy water, and they have also implanted an array beneath the skin in an animal model.

Full story and more details at Physorg