Design Of Automated Nucleic Acid Detection System Based On Microfluidics

As the genetic material of an organism,nucleic acid records the genetic information of the corresponding organism and is also a complete representative of the identity of the organism.Compared with antigen and antibody detection,nucleic acid detection has higher directivity and sensitivity.In recent years,microfluidic chips have been widely used in biological detection due to its trace sample requirement,automatic,better efficiency and lower cost.However,existing nucleic acid detection chips still have insufficient pre-processing capabilities for samples,making it difficult to achieve efficient and automated nucleic acid extraction,purification,and amplification.To this end,this paper has conducted research on the key functional modules in the nucleic acid detection microfluidic chip and designed corresponding automated instrument.In this paper,modular chip design idea is proposed.The nucleic acid detection chip is split into relatively independent functional modules.Each module is designed separately,and a chip manufacturing and hydrophilic modification process based on a 3D printed mold is created.In the design process,COMSOL software was used to simulate the flow in the module,and the influence of shape parameters in the functions of different modules were discussed.The sample addition module,bubble remover module,mixing module,proportional distribution module,and chamber distribution module were designed and optimized.A microvalve which constituted by superabsorbent polymers is designed to reduce the dependence on active microvalves,as it will close passively when swells with water.Besides these,the article also discussed the accumulation of magnetic beads in microfluidic chips,and proposed a method that using low-frequency vibration to disperse the magnetic beads in soft chip.Aiming at the problem of uneven perfusion flow in each chamber of the large-capacity amplification chip,genetic algorithm was applied in optimization.The temperature control method in the isothermal amplification chip and the heat transfer in the chip were mainly studied.In the end,this paper designed a general-purpose nucleic acid analyzer for the current status of micro-fluidic chip supporting instruments.It is compatible with both ordinary and centrifugal microfluidic chips,providing prototype verification for chip designers.Hope this platform can accelerate the design process of nucleic acid detection chip in labs.