This study presents a novel technology to manipulate micro-particles with the assistance from flexible polymer-based optically-induced dielectrophoretic (ODEP) devices. Bending the flexible ODEP devices downwards or upwards to create convex or concave curvatures, respectively, enables the more effective separation or collection of micro-particles with different diameters. The travel distances of the polystyrene beads of 40 μm diameter, as induced by the projected light in a given time period was increased by ~100%, which were 43.0 ± 5.0 and 84.6 ± 4.0 μm for flat and convex ODEP devices, respectively. A rapid separation or collection of micro-particles can be achieved with the assistance of gravity because the falling polystyrene beads followed the inclination of the downward and upward bent ODEP devices.