Magnetically actuated micro-actuators are proposed to propel and manipulate fluid in micro-channels. As the fluid flows at low Reynolds number in such systems, the actuator should move in an asymmetric manner. The proposed actuators are polymer films with embedded magnetic particles, which are actuated by an external magnetic field. Based on the nature of the particles, the films can be either ferromagnetic or superparamagnetic. We have identified four configurations in which the actuator exhibits an asymmetric motion. © 2008 Materials Research Society.