Janus particles, which take their name from a Roman god with two faces, are microscopic 'two-faced' spheres whose halves are physically or chemically different. Now, U.S. researchers have shown that some of these Janus microparticles can move like stealthy submarines when an alternating electrical field is applied to liquid surrounding them. This could lead to new kinds of self-propelling microsensors or means of targeted drug delivery. But read more... You can see above how these particles "move perpendicular to the applied electric field direction with their polystyrene hemisphere (lighter side) forward. The liquid flow around the metal-coated hemisphere (darker side) is much stronger then around the polystyrene hemisphere, driving the particle to move by induced-charge electrophoresis (ICEP) in the direction...