PDMS-glass serpentine microchannel chip for time domain PCR with bubble suppression in sample injection

This paper reports on the development of a low-cost microreactor ( 10 mu l) biochip for DNA polymerase chain reaction ( PCR). The microbiochip ( 20 mm x 28 mm) is a hybrid type that is composed of a polydimethylsiloxane ( PDMS) layer with a serpentine microchannel ( 360 mu m x 100 mu m) chamber and glass substrate integrated with a microheater and thermal microsensor. Because of the hydrophobic chip surface, bubbles are usually created during sample loading in the PMDS-based microchip. These bubbles disrupt the stable biochemical reaction. An improved microreactor chamber was designed using microfluidic simulation. The reactor has a rounded-corner serpentine channel architecture, which enables stable injection into the hydrophobic surface using only a micropipette. The reactor temperature needed for the PCR reaction is controlled within +/- 0.5 degrees C by the LabVIEW software proportional-integrative-derivative (PID) controller. PCR analyses of the sex-determining Y chromosome (SRY) gene and mouse GAPDH gene were successfully performed in less than 54 min by the fabricated microreactor chip.