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根据介电电泳原理,设计了一种梯形叉指的微电极结构,用于粒子的连续分离。首先利用COMSOL软件分析梯形叉指电极的电场分布,确定芯片中电场强度最大值和最小值的位置,并分析粒子在微流控芯片中的受力情况。然后,采用微电子机械系统(MEMS)工艺,以氧化铟锡(ITO)电极玻璃为基底制备了粒子连续分离的芯片。通过实验选取通道障碍的最优尺寸,最后用聚苯乙烯小球和酵母菌细胞为样本进行实验并证明,当混合粒子溶液以3μm/min的速度通过微通道障碍时,由于惯性聚焦全部粒子偏向微通道上方运动,施加6 V的峰值电压和20 kHz的交流信号,此时聚苯乙烯小球和酵母菌细胞皆是负介电泳响应,聚苯乙烯小球所受介电泳力大于流体力便向微通道下方进行偏移,而酵母菌细胞所受流体力大于负介电泳力,其仍然在微通道上方,聚苯乙烯小球和酵母菌细胞分离,分离效率可达到92.8%。
According to the principle of dielectrophoresis, a kind of microelectrode structure with trapezoidal interdigitated fingers was designed for the continuous separation of particles. First, COMSOL software was used to analyze the electric field distribution of the trapezoidal interdigital electrodes to determine the maximum and minimum electric field intensity in the chip, and to analyze the force of particles in the microfluidic chip. Then, using the microelectromechanical system (MEMS) process, indium tin oxide (ITO) electrode glass substrate for the continuous separation of particles prepared chips. The optimal size of the channel barrier was selected through experiments. Finally, polystyrene beads and yeast cells were used as samples and the results showed that when the mixed particle solution passed the microchannel barrier at the speed of 3μm / min, Micro-channel above the exercise, the application of 6 V peak voltage and 20 kHz AC signal, then the polystyrene beads and yeast cells are negative dielectrophoretic response, polystyrene beads subjected to the dielectric force is greater than the force of fluid The migration of yeast cells is greater than that of negative dielectrophoretic force, which is still above the microchannels. The separation efficiency of polystyrene beads and yeast cells can reach 92.8%.