Autonomous microfluidic control by chemically actuated micropumps and its application to chemical analyses.

Autonomous control of microfluidic transport was realized through the use of chemically actuated diaphragm micropumps connected to a network of controlling flow channels. A hydrogen peroxide (H(2)O(2)) solution was transported in the controlling flow channel by capillary action. Upon the solution's arrival at the lower compartment of a micropump filled with manganese dioxide (MnO(2)) powder, a volume change that accompanied the production of oxygen caused by the catalytic decomposition of H(2)O(2) induced inflation of the diaphragm. This in turn caused the movement of a solution in another network of flow channels formed in the upper layer. Micropumps that only exert pressure were also fabricated. By positioning the micropumps at appropriate locations in conjunction with additional flow-delaying components, the ejection of solutions from the reservoir of each micropump could be initiated at coordinated times. Furthermore, the solutions could be transported by the application of pressure from other micropumps. In other words, the information for switching from one micropump to another could be described on the chip in the form of a network of flow channels. This autonomous processing of solutions was demonstrated for enzymatic analyses of H(2)O(2), glucose, and lactate.