Sarah: A biologically active, crab-like microrobot which could crawl through human blood vessels and deliver drugs to specific cellular environments has been created by a team of scientists at Chonnam National University, South Korea. The new robot has a biologically inert polydimethylsiloxane (PDMS) backbone and 6 legs, onto which are grafted individual, living heart muscle cells. The robots are especially unique in that they do not require a power source: instead, the muscle cells utilize soluble glucose in their surroundings to contract and relax, thus propelling the robot forwards. The robots move at an average speed of 100 micrometres per second, and can walk continuously for over 10 days. While not quite at the nanoscale (the robot is approximately 2000 micrometres long in its relaxed state), the creation does show that biologically compatible, functioning robots which operate for extended periods of time in living systems can be generated. The invention was recently published in the journal Lab on a Chip. Any volunteers for clinical testing?!