WiFi Medicine: Implantable Biosensors That Could E-mail Your Doctor | Science Not Fiction | Discover Magazine.

Artificial composites, metamaterials, can be used as implantable biosensors.  Silk is not only tough but is very compatible with most tissue surfaces in the human body.  This combined with highly conductive metals (such as gold, silver, and copper) can be tweaked on a nanoscale level and combined with other materials to respond to frequencies in the terahertz range. As it turns out, proteins in the body resonate at specific frequencies within the terahertz range, making them easy to identify with the right type of biosensors.