微通道内诱导电渗流样品聚焦方法

Sample Focusing Method in the Microchannel by the Induced Charge Electroosmosis Flow

介绍了一种在微通道内基于直流诱导电渗流的样品聚焦方法。在样品微通道两侧壁面布置一对平行金属板,当通道两端施加一定的直流电压时,金属壁面处会形成涡流并挤压样品流动,从而实现聚焦。数值模拟研究表明:当金属壁面尺寸一定时,样品聚焦宽度随外加电场强度的增加而减小,聚焦长度随外加电场强度的增加而增大;当外加电场强度一定时,样品聚焦宽度随金属壁面尺寸的增加而减小,聚焦的长度随金属壁面尺寸的增加而增大;获得相同的聚焦宽度时,采用本方法所产生的焦耳热远低于传统电动聚焦所产生的焦耳热。与传统聚焦方法相比,本方法极大地简化了芯片结构并缩小了系统尺寸,同时降低了焦耳热效应对生物样品的影响,具有较好的应用前景。

A novel sample focusing method in the microchannel by the induced charge electroos- mosis flow was introduced. A pair of parallel metal plates was placed on the sample channel walls. Two vortexes were formed on each metal plate when an electrical field was applied across the channel. The vortexes will squeeze the sample, and the sample focusing effect can be achieved. The numerical simulation shows that when the metal plate size is constant, the sample focusing width will decrease and the sample focusing length will increase with the increase of the applied electric field intensity. When the applied electric field strength is certain, the sample fo- cusing width will decrease and the sample focusing length will increase with the increase of the metal plate size. When the focusing width is the same, the Joule heating produced by this method is much smaller than that produced by the traditional electrokinetic focusing method. Compared with traditional flow focusing methods, this method makes the chip structure simple, decreases the system size and reduces the influence of Joule heating effect on the biological sample, thus it has a good application prospect.