Simulation Of A Continuous-flow Cell-Electrofusion Microchip

Cell fusion is not only widely used in cross-breeding, gene regulation, geneticbiology and food safety, but also becoming key technology in many emerging researchareas. Thus, how to promote cell fusion and improve the fusion ratio, while survival ofthe fused cells is ensured, becomes an important issue.At present, the cell fusion field is to combine the cell fusion technology withemerging microfluidics to form a novel cell-fusion chip technology. Although theapplication of microsystems technology can greatly improve the controllability,observability and the fusion rate of cell fusion, there are several problems still notresolved such as the accurate matching of heterologous cells, quickly obtain a largenumber of fused cells and fusion cells, and effective separation of fused cells’.Therefore, we propose the study of a continuous-flow cell-electrofusion method.We setup a precise matching program for heterologous cells, which is based ondielectrophoretic force based cell control technology and microfluidics. It is combinedwith the one-dimensional micro-electrode array based low-voltage DC pulseelectroporation and on-chip cell separation technology, to realize a novel high efficiencycontinuous-flow cell electrofusion method. As part of this project, the main purpose ofthis paper is to simulate the flow field and electric field of various parts of the chip byusing COMSOL Multiphysics software. And the impact of various parameters on theflow field, and the electric field is also discussed to obtain optimal chip architecturedesign, which may provide some theoretical guidance for future experimental study.On the basis of preliminary studies and Wang’s method, a new continuous-flowcell electrofusion chip model is brought out, in which cells sequentially flow through afew of micro-electrodes formed array to achieve continuous fusion. Aiming at the flowand cell control, as well as requirements of electroporation and fusion, the design of themicrofluidic channel and electrode is simulated. Simulation results provide thecorresponding theoretical support for the design and fabrication of a continuous-flowcell-electrofusion chip. Specifically, this paper mainly includes the following contents:（1） a brief description of entire design and simulation ideas of the continuous-flowcell-electrofusion;（2） establishing a simulation model for the sampling and matchingsegment to explore the impact of different parameters on the flow field, which canprovide theoretical guidance for the choice of chip design and experimental parameters; （3） establishing a simulation model for the electrofusion segment to study the internalelectric field distribution for different microelectrode array design, so as to obtain goodchip design and related parameters.The simulation results show that:（1） in the initial cell injection and processingsegments, the angle between the sheath flow channel and the sample liquid channel aswell as the ratio of L_{side sheath flow}/L_{sample stream}, have no significant effect on the width ofthe focused flow, and it will only affect the flatness of the focused flow. The greater theratio of V_{side sheath flow}/V_{sample flowis}, and the narrower of the width of the focused flow.The width of the focused flow will be less than10μm when the flow rate ratio reaches4:1, and the focused flow tends to be stabile.（2） Subsequent simulation results for cellintersection and pairing segment show that the ratio between the length of the inletchannel and the main channel does not affect internal flow velocity. The larger the angleof intersection between two inlet channels, the more quickly fluid converge is. However,the flow rate changes a little.（3） Simulation analysis of the electric field of the cellfusion segment proves the particularity of the continuous-flow cell-fusion chip.Accordingly, in the chip design, size of the electrodes and distance between adjacentelectrodes must be thought of to match the flow rate. These results may be importantguides for chip design and experimental research.