Numerical simulation of mixing and heat transfer in an integrated centrifugal microfluidic system for nested-PCR amplification and gene detection

摘要

Nucleic acid amplification via polymerase chain reaction (PCR) is one of the essential and powerful methods used in a myriad of bio-assays in clinical laboratories. Application of microfluidic devices in biologically-related processes like PCR can result in the usage of less volume of reactant samples and reduce the processing time. By implementing PCR systems on centrifugal microfluidic platforms, automation and portability can be easily achieved. Although several methods have been developed, most of them are still dealing with challenges of the required high processing time. This study presents the numerical simulation of a fully automated PCR system with the goal of enhancing the mixing quality of the agents comprising primers and samples and accelerating the thermocycling processes through applying a hybrid convective-radiative heat transfer mechanism resulting in an optimized time consumption. In this work, sample manipulation units such as siphon valves and capillary valves are precisely designed and optimized and the desired time of the operation is reduced considerably. In addition, the blending quality of sample and reactants- primers, polymerase enzyme and nucleotides in this case- is enhanced by employing two serpentine micromixers. The efficiency of these micromixers was improved considering rotational speed and geometrical parameters of the corresponding sections of the microfluidic device. Furthermore, instead of using a common convection-based thermocycling process, the novel presented system is designed based on a hybrid convective-radiative heat transfer mechanism and time consumption is significantly minimized and managed by conducing numerical optimizations.