Functional Fluid-Manipulation Using Spiral-Type Magnetic Micromachines as Micropumps, Active Valves, and Channel Selectors

A micro-fluid manipulation technique is introduced using spiral-type magnetic micromachines as pumps, channel selector, and active valves. Magnetic micromachines, also known as microrobots, have been widely studied for biomedical applications because they offer wireless control and microscopic size. Spiral-type magnetic micromachines, which contain a screw mechanism, are synchronized by an external rotating magnetic field (the rotation of an external driving magnet). The screw mechanism means that the machines generate both propulsive and drag forces in a fluid environment. When four micromachines are installed in multi-channels they can be used to control direction and speed of rotation independently. Therefore, by controlling the direction and speed of each machine, it is possible to control the direction of fluid flow and to accelerate/decelerate the flow rate, functioning as an active valve or multiple pumps. The suitability of spiral-type magnetic micromachines for fluid manipulation in microfluid system is verified through various experiments.