A microscopic swimming robot unveiled by Chinese scientists could eventually be used for drug delivery or to clear arteries in humans, say researchers.The 3 millimetre-long triangular machine was constructed by Tao Mei of the Chinese Academy of Sciences, Beijing, and colleagues from the University of Science and Technology of China.The craft is propelled using an external magnetic field which controls its microscopic fins. The fins are made from an alloy that contracts in response to application of the field. Applying the field quickly makes the tiny submersible paddle forwards and gradually switching the field off slowly moves the fins back to their original position.It is possible to control the speed of the craft by altering the resonant frequency of the magnetic field. The next stage is to build a robot with fins that respond to different magnetic field resonances. This would enable an operator to control the fin separately and steer the robot around.
