Flexible LEDs for implanting under the skin

October 18, 2010 by Lin Edwards, Phys.org report

Optical image of an 8x8μ-ILEDs array on a thin PDMS substrate in its on state under deformed conditions. Image credit: Nature Materials, doi:10.1038/nmat2879
(PhysOrg.com) -- 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 research, led by John Rogers of the University of Illinois at Urbana-Champaign in the US, and published today in developed flexible arrays 2.5 μm thick and 100 x 100 μm square, which is much smaller than any commercially available array. They printed circuits directly onto a rigid glass substrate and then transferred them to an inexpensive biocompatible polymer called poly(dimethylsiloxane) (PDMS) to create a mesh-like array of LEDs and photodetectors.

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.

Schematic illustration of the encapsulation of an implantable array of μ-ILEDs. Image credit: Nature Materials, doi:10.1038/nmat2879

Potential biomedical applications for the include implantable patches for monitoring wound healing, for use in diagnosis or spectroscopy, or to control the delivery of drugs triggered by light in photodynamic drug therapy. They could also be used in light-emitting sutures or implantable illuminated plasmonic crystals, and may find application in robotics.

Rogers has recently founded a company in Cambridge, Massachusetts, mc10, to work on commercializing the new technology, which is a goal he regards as "incredibly appealing." Rogers said he wanted the technology to have an impact, and that was the end goal serving as the motivation for the work.

Explore further: Ultrathin light-emitting diodes create new classes of lighting and display systems

More information: Rak-Hwan Kim, et al., Waterproof AlInGaP optoelectronics on stretchable substrates with applications in biomedicine and robotics, Nature Materials, Advance online publication (2010) doi:10.1038/nmat2879

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1 / 5 (6) Oct 18, 2010
... still no fifty-fifty relative trying all unrelative choices, to be read on my renewed website ...
4.4 / 5 (7) Oct 18, 2010
I'm just waiting for my OLED tattoos. :)
1 / 5 (1) Oct 18, 2010
Thats what I'm saying, this opens up a whole new door to body mod.
2.8 / 5 (4) Oct 18, 2010
Beyond body-mod. We're talkin' video tattoos and cuttle-fish people. Get this thing wired to respond to your brain waves and make yourself into the perfect ninja. Of course, you'd have to shave off all your hair and go naked all the time for that to work.
5 / 5 (3) Oct 18, 2010
Of course, you'd have to shave off all your hair and go naked all the time for that to work.

Finally a good reason to do it.
not rated yet Oct 18, 2010
Power supplies?
4.5 / 5 (2) Oct 18, 2010
Caffein powered, just like the rest of me!
not rated yet Oct 18, 2010
I'm waiting for the glowing tattoos that use body heat for energy. I'm not in the mood for getting cyborganized with OLED implantation. Next thing you know, they're shooting you up with nanobots, so you become a technology dependent cyborg. I don't want any "Borg Queen" telling me what to do.
5 / 5 (2) Oct 18, 2010
I'm just waiting for my OLED tattoos. :)

I'm waiting for the period when the OLED's can create light sabres that come out of the skin like Wolverines claws :P
5 / 5 (1) Oct 19, 2010
or to control the delivery of drugs triggered by light in photodynamic drug therapy

To me this is the coolest part of the article. Assuming you could remotely trigger the lights somehow we could have remote controlled drug delivery at very specific locations in the body.

5 / 5 (1) Oct 24, 2010
I'm sure that Science Fiction has made an optimist out of me, but the potential uses for something similar to this seem huge.

A built in display would be a nice step on human integration with machines. Imagine: a wristwatch literally in your wrist, reading texts on the back of your hand, it could be synced with implanted measuring devices so that you could constantly monitor your own vitals.

So many possibilities, all waiting to be realized through technological advancement...
not rated yet Oct 26, 2010
OH..... i cant believe i found this... i live in New Hampshire and if at all possible i would SO love to volunteer to be the first person to have these LEDs implanted.. backlighting the tattoo on my foot wouldnt be a good idea too easy to damage but my other one probably wouldnt be too hard for them to do..

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