It makes me nervous too. I'm not so keen on the idea of circuits enveloped in a silk substrate, which melts into your body leaving just nanometers-thick layers of electronics. But it's for the best, trust me on this one.
Until now, body-embedded circuitry was very limited. The electronics were hard, or had to be separated from the body. With this new technology, flexible circuits can be directly implanted anywhere in the body, protected by a cocoon of silk, which is human friendly. The silk melts away over time, leaving a small substrate of silicon circuitry inside that can't be noticed.
This opens the door to things like LED tattoos, which can monitor and display sugar levels in the bloodstream, other kinds of sensors, and chips that connect to the nervous system. You know, so the government an their extraterrestrial allies can deactivate our will at any time and convert us into alien egg nests. [Technology Review]