A valved responsive hydrogel microdispensing device with integrated pressure source

Stimulus responsive hydrogels provide the actuation pressure required for both valving and dispensing functions in the device presented. The microdispensing device uses an array of responsive hydrogels to deform a flexible membrane above a fluid reservoir chamber. When the microvalve is open, the deformation of the membrane reduces the volume of the reservoir chamber and pushes fluid through the microvalve. When the microvalve is closed, the expanding hydrogel array generates a storable pressure source that will result in fluid dispensing once the microvalve is opened. Experiments determined the pressure generated by this device to be 35 kPa. The device has a stroke volume of 45 μL, and is able to hold the pressure for over 24 h.