Edible computers
This is a link to some research about edible electronics: http://eng.auburn.edu/news/2010/09/fergusedibleelectronics.html
I think computing must move in this direction if we are to survive as a species, without debilitating birth defects due to our computer processors ending up in our bloodstreams as they currently do. William McDonough proposes another route in the book Cradle to Cradle: keep the biological nutrient flows separate from the technological nutrient flows. So far that hasn't worked, but might if residents made decisions trumped CEOs decisions.
Another example: this TED talk about making play dough circuits: http://www.ted.com/talks/lang/en/annmarie_thomas_squishy_circuits.html
And there's the whole meat printing and growing-tissues-in-test-tubes efforts under way, which are edible (or at least gracefully biodegradable) circuits, from one perspective.
I guess the question is: can those materials replace current materials to make computers as we know them, or would we have to re-design computers in order to make them with biocompatible materials?