Experimental study on the heating/cooling and temperature uniformity performance of the microchannel temperature control device for nucleic acid PCR amplification reaction of COVID-19

Abstract

The nucleic acid detection is an effective way for the prevention and control of COVID-19. PCR amplification is an important process in the nucleic acid detection. At present, PCR amplification has the problem of low heating/cooling rates, and poor temperature uniformity. This paper proposes a microchannel temperature control device for the nucleic acid detection. Five groups of parallel serpentine channels are used to increase the cooling rate of the PCR amplification. A gradual thermal conductivity design is applied to the reaction module to increase the temperature uniformity. The experimental results show that the best temperature uniformity is obtained when the materials of the inner and outer layers of the reaction module are copper and aluminum alloys, respectively. The limit and average heating/cooling rate are 7.2, 6.12, 5.52 and 5.28 °C/s, respectively, when the input power of the thermoelectric cooler is 11.07 W/cm2, the temperature and flow rate of the cooling water are 15℃ and 700 ml/min, and the thermal conductivity of the thermal grease is 6 W/(m·K). Compared with the commercial fan-fin cooling method, the limit and average heating/cooling rates are increased by 38.02%, 80.82%, 86.49% and 208.77%, respectively, with the help of microchannel cooling method.