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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 sample focusing method based on direct current induced electroosmotic flow in microchannels is introduced. A pair of parallel metal plates are arranged on both sides of the sample microchannel wall. When a certain DC voltage is applied to both ends of the channel, eddy currents are formed on the metal wall surface and squeeze the sample to flow to achieve focusing. The numerical simulation shows that when the size of the metal wall is constant, the focusing width of the sample decreases with the increase of the applied electric field intensity, and the focusing length increases with the increase of the applied electric field strength. When the applied electric field intensity is constant, the sample focusing width varies with the metal wall The length of the focusing increases with the size of the metal wall; when the same focusing width is obtained, the Joule heat generated by this method is far lower than the Joule heat generated by the traditional electric focusing. Compared with the traditional focusing method, this method greatly simplifies the chip structure and reduces the size of the system, while reducing the Joule heat effect on biological samples, has a good prospect.