Rapid Customization And Control Mechanism Of Microdroplet Chip For 3D Cell Culture

The microdroplet chip is a branch of microfluidic technology in which the generated microdroplets serve to transport and carry the reaction vessel.Microfluidic chips are widely used in gene mutation detection,genotyping,DNA sequencing,cell culture,cell sorting,and cell state research.With the increasing demand for and functionality of microfluidic chips,past manufacturing methods and manufacturing processes have clearly failed to meet social and experimental requirements.This paper proposes a full PDMS microdroplet cell culture chip for 3D cell culture.This chip is prepared by SLA photocuring 3D printing technology,which can quickly customize various chips required for experiments.The main research work of this thesis is as follows:Firstly,according to the relevant theoretical basis of the existing microfluidic chip and the mechanism of droplet formation in the microdroplet chip,the flow channel structure is designed for the microdroplet chip.By comparing the differences of the three common droplet formation forms of the T-channel method,the flow focusing method,and the coaxial focusing method,the flow focusing method is selected as the droplet formation method.The flow path of the "Y"type flow path and sinusoid in the chip is to increase the degree of mixing of the cell suspension with the sodium alginate solution.Secondly,the two-phase flow and level set module of COMSOL Multiphysics software is used to simulate the designed micro-droplet chip.Through the reasonable selection of the simulation module,the basic fluid parameters and the boundary conditions,the simulation of the droplet formation is simulated.process.It can be seen from the simulation results that micro-droplets of different sizes can be accurately generated by controlling the flow velocity of the dispersed phase and the flow velocity of the continuous phase.Third,a full PDMS chip was prepared by injection molding,and the male mold was prepared by photocuring 3D printing technology.Compared with the traditional micro-droplet chip preparation process,the use of 3D printing technology to prepare the micro-droplet chip can save manufacturing cost and time cost.The substrates and cover sheets of different proportions of PDMS and the materials for making the male molds herein can improve the bonding strength and bond synthesis power of the microdroplet chips.Microdroplet forming and manipulation experiments were performed using the prepared microdroplet chip.From the experimental results,it can be known that micro-droplets of different sizes can be accurately generated by controlling the flow velocity of the dispersed phase and the flow velocity of the continuous phase.This result is basically consistent with the results of the simulation.Finally,a solution such as a chondrocyte suspension was inj ected to verify the performance of the whole PDMS microdroplet chip in biological culture and the manipulation of the microdroplets was achieved by controlling the flow rates of the dispersed phase and the continuous phase.It has been verified by experiments that the designed chip can meet the requirements of the experiment,and it can be observed that the microdroplets of sodium alginate and the calcium chloride solution cross-link reaction and the micro-droplets become microspheres having a 3D stereo structure.The formed microspheres were immobilized on a biological scaffold made of calcium silicate and polyvinyl alcohol.Subsequently,the state of the cells cultured for 0h,24h and 48h was observed,and it was observed that the chondrocytes grew well in the microsphere droplets.