US Patent 7648619 Hydrogel-driven micropump

A hydrogel-driven micropump, comprising: two fluid chambers; a fluid channel, connecting the two fluid chambers; a first substrate plate and a second substrate plate, which are glass wafers produced by micromechanical working, each having accommodation chambers which are filled in hydrogel which are placed next to the two fluid chambers and connected by inward extending bridges, with electric terminals leading to the accommodation chambers; a middle substrate, sandwiched between the first and second substrate plates and made by a bulk micromachining process, having separated accommodation chambers close to ends thereof. A separating block is placed between the accommodation chambers. The middle substrate between the first and second substrate plates forms a micropump body. All of the substrates are separated by membranes. The accommodation chambers for electrophoretic fluid are located between the membranes and the first and second substrate plates, respectively, and insulating material. An electrophoretic fluid channel is left between the membranes and the bridges. The fluid channel is placed within the middle substrate between the membranes. The first substrate plate has through holes from outside to the two fluid chambers, allowing fluid to be injected.