Polymerase chain reaction (PCR) is a technique in nucleic acid analysis which revolutionized molecular biology due to its numerous applications in medicine, biomedical devices, and forensics. PCR is used to amplify a considerable number of specific DNA target sequences from a minimal amount conducted by apparatus called thermal cyclers. The process involves repetitive heating and cooling the sample according to a specific protocol. Protocols usually consist of three steps:​ a denaturing step at 92–96°C, an annealing step at 52-58°C, and an extending step at 70-80°C. Microfluidic PCR devices suggest significant benefits over conventional thermal cyclers, such as smaller size, rapid heat transfer, portability, and lower sample consumption. However, most developed microfluidic chips require various external components to operate. They are also unsuitable for mass production due to their high cost and complex fabrication methods.

In this study, a disposable, low-cost, and easy-to-fabricate microfluidic PCR is developed. The device comprises a micromixer, reaction well, microheater, and temperature control system. Several methods have been implemented to reduce the chance of sample-to-sample cross-contamination. The designed control system is able to perform PCR at any temperature inside the ordinary working range of PCR protocols. The microheater is fabricated by patterning gold on a glass slide which has been modified through a series of experiments to provide temperature uniformity with ±1°C precision across a circular area that houses the PCR reaction chamber. The micromixer performance was analyzed at different flow rates and channel heights among several structures which culminated in final mixing efficiency of 94.17%. Finally, the reliability and repeatability of the microfluidic device were verified by amplifying λ DNA, where even the developed device outperformed conventional thermal cycler in specific protocols.