Polymerase Chain Reaction Microchip and PID Controller Based Thermal Cycler Design

Abstract

Numerous specific procedures are needed for nucleic acid detection using traditional approaches. Because of the time and instrumentation requirements, poor detection limits, and other factors, they are behind in creating point-of-care (POC) testing. In addition, some of these traditional approaches can be extremely sensitive. Microfluidic technologies are being used to overcome these challenges by enabling the efficient and automatic performance of all analytical stages, such as sample pre-treatment, reactions, separations, and diagnostics in microchannels on a small chip. The use of microfluidics technology in polymerase chain reaction (PCR) technology has resulted in many advantages. PCR microchips and portable thermal cyclers that can be used for POC testing have enabled faster amplification with accurate results. This paper proposes a low-cost, fast enough thermal cycler for POC testing that uses a polymer-glass microchip and an affordable Peltier element to quickly heat samples. A laser cutter was used to build the microchip needed to perform PCR, which was designed using a computer-aided design (CAD) software. The heating and cooling elements employed in the creation of the thermal cycler were Peltier elements, heat sink, centrifugal fan, and CPU fan. A microcontroller and H-Bridge modules were used to control the temperature with the help of proportional-integral-derivative (PID) controller algorithm. After that, the circuit components and PID control algorithm—which was created for temperature control—were combined to create the PCR cycle. The analysis focuses on the heating and cooling performances of suggested thermal cycler.