Microfabricated In-Channel Structured Polydimethylsiloxane Microfluidic System for a Lab-on-a-Chip

In this paper, the fabrication of microfluidic system integrated with micropump and microvalve on the same substrate and its high performance are described. The microfabricated microfluidic system has been optimized for application in capillary electrophoresis-electrochemical detector (CE-ECD), polymerase chain reaction (PCR) and microcantilever. The system is realized by means of a polydimethylsiloxane (PDMS)-glass chip and indium tin oxide heater. The pumping rates of the proposed micropump are measured as functions of the frequency and the duty-ratio of applied voltage. The performances of the microvalves are characterized under the on/off alternation with the applied power of the indium tin oxide (ITO) heater. The flow rate gradually decreases as the applied heater power increase. The optimized membrane thickness for microfluidic system is 350 mu m. At this condition, the power of the cut-off flow in microvalve is 400 mW and the 70 nl/min of maximum pumping rate is observed at a duty ratio of 4% and a frequency of 4 Hz for the applied pulse power.