Imagine a microscopic device injected into your body that searches for genetic malfunctions in your cells. If it finds any, it emits a green light to highlight the diagnosis. Weizmann Institute scientists have developed such a device – and are now working on upgrading it to destroy the cancerous cells.
http://wis-wander.weizmann.ac.il/a-genetic-device-performs-dna-diagnosis#.USOPN_L67hE
http://www.nature.com/srep/2012/120907/srep00641/full/srep00641.html