Structure Design And Theory Of Microfluidic Cell-trap Array Chips

Focusing and sorting cells or particles utilizing microfluidic phenomena have been flourishing areas of development in recent years.These process are largely beneficial in biomedical applications and point-of-care miniaturized diagnostic devices and rare cell enrichment techniques.Based on the theory of fluid dynamics,solid mechanics,fluid-solid coupling theory,particle-fluid two-phase flow and Newton's law of motion,a mathematical model of cell transport and capture in the microfluidic cell-trap array systems proposed.On the other hand,a series of index parameters are proposed to meet the requirements of the chips' application,such as the capture efficiency and loading time of the cell,the pressure and velocity distribution of the fluid,the velocity and displacement of the cell,also the deformation and the wall shear stress the cell suffered and so on.These parameters should be considered during the structure design.Based on the cell capture theory and parameters,three types of micro-trap structures,such as U-type seamless,single-slit and double-slit,and kinds of arrangement microarray capture chips were designed.Based on the commercial software COMSOL,a numerical model of the single cell capture process was established.The effects of the inlet velocity and the trap structure on the capture results and the corresponding process parameters were investigated.On the other hand,based on the experimental study,the effect of chip structure and array arrangement on chip capture efficiency and loading time is studied.The numerical simulation results show that the double-slit trap structure has better capture efficiency when the velocity range is large,U-shaped with single-seam is the next,while the U-shape seamless is the worst.Moreover,the double-slit trap structure also performed better in the relevant process parameters.The experimental results are in good agreement with the numerical results.In addition,the experimental results also show that double-slit is the most efficient and the loading time is also the shortest,U-type single slit also has a better performance in the capture efficiency and loading time,but its indicators of cell stress and other inferior Double-slit,U-type seamless traps capture has the lowest efficiency.When the spacing ratio is 1,the fluency of the channel is the best.Finally,the double-slit capture trap has the best capture efficiency and corresponding parameter index.The designed chip can be applied to the corresponding analysis of cells.The research methods and results of this paper can provide the reference for the next chip structure design and the practical application of the chip.