| Magnetic cell sorting is an important method for cell separation.It's based on the principle of high gradient magnetic field sorting,within the specific binding of target cell antigen and antibody,target somatic cell can be magnetically labeled by magnetic beads specifically,thus the target cells are magnetic,which can be separated from non-target cells by magnetic force acting on the magnetic beads in the magnetic field.This method has the advantages of high sorting purity,good repeatability,convenient and rapid operation,and suitable for continued culture after separation.Magnetic separator is currently only owned by a few foreign companies which have mature products,while China is still in a blank.Therefore,it is urgent to study the theory,technology and performance of magnetic separation deeply and comprehensively,and propose the corresponding solution.In this paper,the present magnetic cell separation situation at home and abroad will be introduced,and within the basic principle of somatic cell sorting,the realization method of automatic somatic magnetic separation apparatus is put forward,and experimental analysis is carried out.The main research works are as follows:Analyzed the mechanism of magnetic separation process deeply,built the micro model of separation column,the finite element simulation of magnetic field,fluid field and particle motion is performed in Comsol software.The magnetic field and fluid field distribution are calculated by steady-state analysis.The motion process of particles is obtained by transient analysis.Analyze the variation of magnetic force and adsorption rate with external magnetic field,the relative permeability of steel balls,the magnetic beads diameter,the steel balls diameter and the initial fluid velocity.Put forward the specific design idea and method of the magnetic separation equipment.The sorting device consists of a magnetic sorting unit,a sample conveying unit,a computer software control unit and an instrument case.The core of the magnetic sorting unit is a sorting column and a magnet.Magnets are used to provide external magnetic fields.The separation column is used to realize the high gradient magnetic field and generate enough magnetic force for the magnetic beads.The sample conveying unit is used for automatic transmission of the cell liquid and process controlling,it includes piping system,pinch valve and peristaltic pump.Computer software control unit is used to provide the interface of human-computer interaction,and realize the process of software control to instrument sorting.All parts are arranged in the shell of the instrument and cooperate with each other to realize the complex sorting process.At the same time,a photoelectric magnetic bead concentration measuring device was set up.Based on the turbidimetric method,the intensity of transmitted light was measured,and the ratio of the intensity of the transmitted light and the intensity of source light was taken as the concentration reference.The experimental results showed that it is consistent with the exponential change rule of turbidity and can be used for actual measurement.The magnetic beads separation experiment and cell sorting experiment were carried out by the developed somatic magnetic separation apparatus.After one stage of column separation,the magnetic beads sorting purity can reach 95%or more,which means the magnetic separation efficiency is good.Also,within the appropriate concentration of magnetic beads and experimental conditions,the results of cell sorting shows that the recovery rate can reach 30%,for CD3 antibody cells,the positive rate can reach 72.2%,it achieves good results with the device.Theoretical analysis and experimental results show that the proposed magnetic separation method and its evaluation method are correct and feasible.The results of this paper are expected to fill the gaps in this field,and have excellent academic value and reference significance for further research. |
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