New cost effective design of PCR heating cycler system using Peltier plate without the conventional heating block

Temperature control is a critical factor in PCR for efficient DNA amplification. The main aim is to achieve tight control and high rate of heating and cooling for a portable, cost-effective PCR device. This speed depends on reduction of the thermal mass of the PCR heating part. The common methods used to decrease the device's thermal mass or heating/cooling time are to improve desirable device structural design and to choose a better heating and cooling mechanism with robust controller. Increasing the thermal mass provides a good temperature distribution on the heater surface, but it delays the heat transfer. Therefore, removing thermal mass makes the controller struggle to provide a high temperature uniformity distribution on Peltier surface. In this paper, we provide a cost-effective PCR heating/cooling system using Peltier element. This system is controlled using adaptive FLC with bang-bang as a hybrid controller to provide good accuracy with maximum available temperature changing rate. The results show that in cooling, the adaptive FLC with bang-bang controller is faster by 20 % than the normal PD-like FLC, however in heating it is faster by 5 to 10 %. The adaptive FLC provided steady state error 3 % and 1.5 % less than the normal FLC at denaturation and annealing steps, respectively. Temperature distribution is tested using thermal camera. The device is validated by performing conventional PCR. The amplification product was analyzed by electrophoresis on a 1.5 % agarose gel then stained with ethidium bromide and the products show successfully amplified.