Small Steps Towards Medical Nanorobots
As engineered nanoparticles increase in complexity, they will at some point be sophisticated enough to be considered true medical nanorobots. That's still in the future, but you can see that the process is underway: "Scientists have developed nanometer-sized 'cargo ships' that can sail throughout the body via the bloodstream without immediate detection from the body’s immune radar system and ferry their cargo of anti-cancer drugs and markers into tumors that might otherwise go untreated or undetected. ... The idea involves encapsulating imaging agents and drugs into a protective 'mother ship' that evades the natural processes that normally would remove these payloads if they were unprotected ... These mother ships are only 50 nanometers in diameter, or 1,000 times smaller than the diameter of a human hair, and are equipped with an array of molecules on their surfaces that enable them to find and penetrate tumor cells in the body. ... We are now constructing the next generation of smart tumor-targeting nanodevices. We hope that these devices will improve the diagnostic imaging of cancer and allow pinpoint targeting of treatments into cancerous tumors."
Link: http://www.sciencedaily.com/releases/2008/09/080911185104.htm