Implant anything large (that is, as large as a human hair) in the body and there will be problems such as irritation or outright rejection. However if you implant something very very small – nanoscale silicon wiring – it’s too small for the immune system to notice it. Do another clever thing; lay out the silicon wiring on tiny and very thin pieces of pure silk. The silk makes it easy to insert into the body, and when wet it will conform to the surface of the tissue on which it is applied. Even better, the silk will naturally and quickly disappear, leaving the nanocircuitry in place. This is the essence of a nifty piece of work done by an extensive research collaboration…
The researchers, which hail from a handful of institutions including the University of Pennsylvania and the University of Illinois at Champaign-Urbana, are now tinkering with electrodes built on silk to serve as interfaces for the nervous system. Existing electrodes, employed in procedures like deep-brain stimulation in Parkinson’s patients, generally sit atop or sometimes pierce the tissue. Arrays of silk-implanted electrodes could integrate better with biological tissues, conforming to the brain’s canyonesque architecture to reach regions that were previously inaccessible.
Most electronics must be “canned,” or encased so they don’t trigger irritation inside the body, and also so the body doesn’t interfere with the device’s performance. But by building an array of one millimeter-long, 250 nanometers-thick transistors on a thin silk substrate, the researchers have demonstrated that their circuitry is thin enough fly under the body’s immune reaction radar.
[Source: Popular Science]
Because the implant is ultra-thin, small, and conforms to the shape of tissues, this approach has a huge range of possible applications from sophisticated brain implants to uses within the dermis (skin). The tricky part will be the reliability and functionality of the implanted silicon circuits, in particular connecting them to some kind of control or monitoring device (internal or external). The approach is in the laboratory phase of development.