Thermally actuated microfluidic system for polymerase chain reaction applications

In this chapter, an optoelectronic Lab-on-Chip system for DNA amplification integrating a polydimethylsiloxane microfluidic structure with indium tin oxide heaters on a 5 × 5 cm2 microscope glass slide is presented. The microfluidic structure comprises a channel for the fluid handling and a reaction chamber for the polymerase chain reaction (PCR). Two lateral heaters, located at the inlet and outlet positions of the chamber, actuate the valves and allow the chamber isolation, while the last one, positioned below the chamber, is dedicated to the PCR thermal cycle. In order to optimize heaters and valves geometry, the temperature distribution over the heaters and the membrane valve deformation have been studied using the commercial software COMSOL Multiphysics. The microfluidic structure has been fabricated by using soft lithography techniques on one side of the glass substrate, while the thin film heaters were deposited and patterned on the opposite glass side. Experiments show that valve activation begins around 60 C, and complete closure is observed around to 100 C, without any loss of liquid from the chamber. © 2014 Springer International Publishing Switzerland.