集成惯性聚焦结构的介电泳微流控芯片的粒子连续分离

设计并制造了一种带有惯性聚焦结构的介电泳微流控芯片,以实现不同介电性质的粒子连续分离.采用MEMS工艺制作了介电泳微流控芯片:通道入口侧壁设置一对梯形结构使经过的粒子受惯性升力的作用聚焦到通道两侧;通道底部光刻一组夹角为90°的倾斜叉指电极产生非均匀电场,利用介电泳力和流体曳力的合力使通道两侧不同的粒子发生角度不同的偏转进入不同通道,从而实现分离.将酵母菌细胞和聚苯乙烯小球作为实验样本,分析了流速和交流电压对分离的影响,确定了二者分离的最优条件并进行分离.实验结果表明,将电导率为20μS/cm的样本溶液以5μL/min的流速注入到通道中,施加6 Vp-p、10 kHz的正弦信号,酵母菌细胞沿电极运动至夹角处后沿通道中心排出,聚苯乙烯小球沿通道两侧排出,成功实现分离,平均分离效率达92.8％、平均分离纯度达90.7％.

Continous Particles Separation of the Dielectrophoresis-Based Microfluidic Chip with Inertial Focusing Structure

A dielectrophoresis microfluidic chip with inertial focusing structure was designed and fabricated to realize the continuous separation of particles with different dielectric properties. The dielectrophoresis microfluidic chip was fabricated by MEMS:a pair of trapezoidal structures is provided at the inlet side walls of the channels to allow the passing particles to be focused by inertial lift forces on either side of the channel. At the bottom of the channel,a set of tilted interdigitated electrodes with an included angle of 90 ° were etched to produce a non-uniform electric field. By using the force of the dielectrophoretic force and the fluid drag force,the different particles on both sides of the channel are deflected into different channels at different angles so as to realize the separation. Saccharo-myces cells and polystyrene beads were used as experimental samples. The effects of flow rate and AC voltage on the separation were analyzed. The optimal conditions for the separation of the two were determined and the separation was carried out. Experimental results show that the yeast cell is discharged along the channel center at the angle be-tween the electrode and the electrode. Polystyrene beads are discharged along the side of the channel. A sample so-lution with a conductivity of 20 μS/cm was injected into the channel at a flow rate of 5μL/min. Applying 6 Vp-p, 10 kHz sine signal. The average separation efficiency reached 92.8％ and the purity reached 90.7％.