Continuous on-chip micropumping through a microneedle

Microneedles are promising microfabricated devices for minimally invasive drug delivery applications. Microneedles can be integrated into a variety of devices. However, any portable drug delivery device with integrated microneedles will need an equally compact means to deliver the therapeutics. This work presents microneedles integrated with an on-chip MEMS positive displacement micropump for continuous drug delivery applications. The generation and collapse of thermally generated bubbles with flow rectified by directional check valves are used to achieve net pumping. Visualization methods have observed net flow rates of water out of a microneedle at approximately 1.0 nl/s with a pressure of 3.9 kPa. In addition, continuous pumping was achieved for more than 6 hours. The heaters operated for over 18 hours (15,000 cycles) without failing.