Semi-disposable microvalves for use with microfabricated devices or microchips

The design, fabrication and performance characteristics of a semi-disposabl e CNC (computer numerical control) machined plexiglass microvalve system fo r use with microfabricated devices or microchips designed for human cell is olation and DNA amplification systems are described. Unlike other silicon c hip-based microvalve systems, the CNC machined microvalve system is easy to fabricate, and it does not require a clean-room environment and complicate d microfabrication procedures. The non-silicon-based microvalve comprises a disposable CNC machined plexiglass base and a flexible plastic membrane. T he microvalve was formed from two discontinuous micro-channel components. T he plexiglass used for fabrication does not inhibit biochemical reactions a nd extensive experimental how studies were performed to optimize the design of the microvalve assembly so as to allow controlled flow. Different types of plastic membrane and eight different discontinuous micro-channel valve geometries were investigated and an optimum design was chosen based on the experimental results. The final design of the microvalve has minimal dead v olume (less than 0.16 mu l). We have demonstrated that the CNC machined ple xiglass microvalve system can process microliter and sub-microliter sized s amples of human whole blood without attendant problems, such as loss of sam ple on the microvalve system and loss by evaporation.