A bi-polymer micro one-way valve

We have developed an in-plane bi-polymer check-valve for controlling microfluidic flow and preventing contamination between solutions by tilizing the elastic force of a swollen hydrogel. The valve was created using microfluidic tectonics, a fabrication procedure that allows construction f microscale components and autonomous systems using liquid-phase photopolymerization and in situ fabrication. The valve is composed of rigid arts (poly isobornyl acrylate) that provide a base frame, and compliant parts (hydrogel) that seal off the channel. The rigid part was fabricated y filling a polycarbonate cartridge with the isobornyl acrylate based prepolymer followed by UV light exposure through a photomask forming chamber. To obtain well-defined chamber walls, a double exposing method (first exposure under lower UV dosage, then second exposure after lling the formed channel with DI water) was applied. Next, the chamber was filled with the hydrogel prepolymer mixture and exposed to UV ight through a valve mask to define the compliant component of the device, resulting in an in-plane bi-polymer structure. The valve is actively ssembled in situ providing precise sealing using low resolution lithography fabrication methods. Valve performance can be adjusted by varying he device geometry. Due to its in-plane structure and in situ fabrication process, microfluidic devices incorporating microvalves can be designed nd fabricated conveniently. 2006 Elsevier B.V. All rights reserved.