Japanese scientists have developed a robot smaller than a grain of rice that can travel through veins to hunt down a tumor and then destroy it. The robots, which are based on cylindrical magnets, resemble small screws and are capable of burrowing through 2 centimetres in just 20-seconds. Kazushi Ishiyama, the scientist who developed the robots, says they are small enough to be introduced into the bloodstream by a hypodermic needle and then steered around the body magnetically. He believes that the robots could be used to deliver drugs to infected tissues, or target tumors by burrowing into them and unleashing a hot metal spike to destroy them.
SOURCE/REFERENCE: Reported by www.bbc.co.uk on the 13th June 2001