Simulation analysis and experimental verification of thermodynamic characteristics of integrated droplet digital PCR chip

In order to reduce the influence of the thermal conductivity of the digital polymerase chain reaction (dPCR) chip material and the temperature distribution of the droplet collection chamber on the amplification effect, an optimized integrated dPCR chip was designed. The heat conduction of the designed dPCR gene chip was simulated by COMSOL finite element model, which provided theoretical basis for the design and fabrication of the chip. Three-dimensional ht models of dPCR microarray under steady state and transient conditions were established. The thermodynamic simulation of dPCR gene chip was carried out by changing the material, thickness, structure and width of droplet collection chamber. During the high temperature denaturation stage of amplification, the temperature characteristics were analyzed, and the surface temperature, heating curve, isotherm, thermal expansion and other results of the dPCR gene chip were obtained, and the structural parameters of the chip design were optimized to provide guidance for the subsequent chip design. The results showed that the internal temperature uniformity of the COC sample was higher than other materials. The chip has a thickness of 2 mm and the collection chamber has a width of 4 mm, which was better suited to meet the requirements of PCR reaction. The PCR amplification device was established, and the uniformity of temperature distribution of the fabricatedchip was verified by thermal imager. The results showed that the heat conduction speed was fast, the heat conduction was uniform, and the uniformity was less than ± 0.5 °C. Therefore, under the premise of meeting the quantity of microdroplet generation, the chip designed in this paper has excellent heat conduction performance.