Polydimethylsiloxane microfluidic system with in-channel structure for integrated electrochemical detector

The purpose of this work is to integrate a microfluidic system with biochemical sensors. The proposed microfluidic system consisted with micropumps, microvalves, and microchannels can be applied to PCR, CE-ECD, and microcantilever sensors. This microfluidic system has advantages in terms of its ease of fabrication and bonding process, as well as its biocompatibility. A thermopneumatic-actuated micropump with diffusers was fabricated. The optimum pumping rate of approximately 3.0 l/min was obtained with an inlet width of 60 μm at a 3 Hz frequency. In addition, the microvalve accommodates a paraffin chamber that utilizes the large volume expansion associated with the solid-to-liquid phase transition of paraffin. Between the two different valve seat diameters, the 2 mm diameter showed better performance, where the flow rate reached zero when the applied power supply was approximately 300 mW, than the smaller valve seat diameter of 1.5 mm, which required a higher power supply of 350 mW.