Research On Manufacturing Process Of Integrated Microfluidic Chip Based On 3D Printing

In recent years,microfluidic technology has been widely used in biomedicine and medical diagnosis.The traditional microfabrication technology has the disadvantages of high cost,long processing cycle and no portable characteristics,which limits the popularization and application of microfluidic technology^[1].Compared with traditional micro-processing technology,3D printing microfluidic chip technology can process three-dimensional complex structures,fully automatic integrated manufacturing,and low preparation cost.However,the microfluidic chips prepared by 3D printing technology still have problems such as microchannel collapse and blockage,unsatisfactory surface flatness,and poor hydrophilicity.As an important component of microfluidic chips,micromixers are mostly complex three-dimensional structures.Compared with other types of microfluidic chips,the preparation process requirements are higher.In this thesis,the 3D printing micromixer is taken as the research core.Aiming at the fused deposition technology,the preparation scheme of printing integrated microfluidic chip based on the principle of sacrificial layer is proposed,and the optimal printing parameters are obtained through experiments.The printing layer height is100μm,the printing temperature is 215°C,and the printing speed is 40mm/s.The optimal post-treatment process parameters are polishing machine mode（isopropanol solution concentration 90%,polishing time 15min;anhydrous ethanol concentration 90%,polishing time15min）,soaking mode（isopropanol solution concentration 90%,polishing time 90s;anhydrous ethanol concentration 90%,polishing time 70s）,which effectively improves the microchannel collapse,poor surface flatness and poor hydrophilicity of the microfluidic chip prepared by 3D printing technology.Then,based on these process parameters,an integrated closed microfluidic chip was prepared.However,due to the complex structure and the small channel accuracy of the chip,the closed sacrificial layer structure with channel size accuracy below 600μm can not completely remove the sacrificial layer material.The integrated microfluidic chips scheme based on FDM technology can only achieve the preparation of integrated microfluidic chips with a minimum size of 600μm.For SLA photocuring technology,the photosensitive resin is directly cured by ultraviolet light source,and the residual resin in the channel is removed by ultrasonic cleaner to realize the hollow channel structure,and the integrated preparation of microfluidic chip is completed.The influence of printing process parameters and post-treatment process parameters on chip structure forming is studied through experiments.It is determined that under the current process environmental conditions,the ambient temperature is 25°C,the humidity is 50%RH,and the printing layer height is 50μm.The best printing process parameters,ultrasonic cleaning time 20min,power 30w,cleaning liquid for alcohol and water solution ratio 1:1,for the best post-treatment process parameters.Subsequently,the functional test of the integrated microfluidic chip prepared by SLA technology was carried out.The fluorescein isothiocyanate solution and rhodamine B solution were injected into the micromixer to be mixed into a brown test solution,which verified the normal conductivity and mixing function of the micromixer.Finally,the full text work is summarized.