Design and fabrication of microfluidics system integrated with temperature actuated microvalve

This paper presents the design and fabrication of a microfluidic structure on a glass substrate for fluid handling in lab-on-chip systems. A polydimethilsiloxane microfluidic network hosts a thermally actuated microvalve on one side of the glass slide, while, on the opposite side, a thin film metal heater acts as heat source for the actuation of the microvalve. The design of the system has been carried out using COMSOL Multiphysics. The width of the microchannel has been optimized taking into account the deformation of the valve membrane and the temperature needed to actuate the valve. In order to overcome the fluid leakage due to the shape mismatch between the deformed valve membrane and the rectangular cross-section of the channel, a microchannel with round-shaped cross-section has been simulated and subsequently fabricated by using a mold of positive photoresist AZ® 40 XT. The reliability of the complete device has been tested and verified on several fabricated devices through repeated cycles of closing and opening of the microvalve.