Printed in the united states of america continuous-flow microfluidic polymerase chain reaction chip using dry film resist on glass substrate

Continuous-flow microfluidic polymerase chain reaction (PCR) chips have considerable promise because of their speed and low evaporation compared with chamber-type chips. However, conventional polydimethylsiloxane (PDMS)-based chips require a time-consuming and complex manufacturing process including steps such as reactive ion etching to overcome the hydrophobic nature of PDMS. Here, we report the use of dry film resist (DFR) instead, which is inherently hydrophilic and has lower heat conductivity than silicon. The proposed device consists of DFR microchannels created by photolithography, with integrated Pt heaters on a soda-lime glass substrate. The device cycles fluid through zones with different temperatures (94 °C, 55 °C, and 72 °C), which are controlled by a proportional-integral-derivative (PID) controller. The chip is 60 x 15 mm in size, with channels having a width and depth of 200 μm, a total length of 0.75 m, and a volume of 30 μl. The temperature distribution across the chip was investigated by experiments and numerical simulation. The proposed continuous-flow chip is cost effective because it is simpler to fabricate than PDMS-based devices, and it is faster than chamber-type PCR chips, which require considerable time for heating and cooling the chamber. This PCR chip is applicable to DNA amplifiers.