Microfluidicchips for cells capture using 3-D hydrodynamic structure array

Jingdong Chen, Di Chen, Tao Yuan, XiangChen, Jun Zhu, Andreas Morschhauser, Joerg Nestler, Thomas Otto and ThomasGessner

Microfluidic chips for cells capture using 3-D hydrodynamic structure array.pdf

摘要：

   为了捕获一定数量的目标细胞，设计了两种在垂直方向产生高度差的三维捕获结构微流控芯片。芯片采用两层结构，设计如下：第一层支柱结构为与第二层结构相对应棱边的结构，其高度可以根据捕获细胞的尺寸进行调整；第二层结构为“U”型结构，并在顶端处设计了尖三角结构。另一种捕获结构在第一种捕获结构的前端设计了导流帽结构。两层结构不仅制备加工简单，成品率更高，而且更容易根据捕获细胞的尺寸进行调节。根据哈根-泊肃叶定律对捕获结构进行了流体力学分析，并利用COMSOL Multiphysics软件对芯片的流场分步进行了模拟。和单个捕获结构相比，捕获结构阵列能够通过改变流场分布增加细胞的捕获数量。最后利用酵母菌对芯片的性能进行了测试。在1 μl/min的流速下，无帽捕获结构芯片的捕获酵母菌的效率达到71%，而有帽捕获结构芯片的捕获酵母菌的效率只有25%，因为流体比较容易从导流帽的后面流道后一排结构。当流速增加到2 μl/min时，有帽捕获结构芯片的捕获效率有所减小，但无帽捕获结构芯片却有所增大。为了能够有效捕获细胞，防止细胞流过捕获结构，捕获结构底部和玻璃基片之间间隙的高度要小于细胞尺寸，而这很容易通过调整制备过程中第一次SU-8胶的厚度而实现。

Abstract

         Microfluidic chips were designed and fabricated to capture cells in a relative small volume to generate the desired concentration needed for analysis. The microfluidic chips comprise  three-dimensional (3-D) cell capture structures array fabricated in PDMS. The capture structure includes two layers. The first layer consists of spacers to create small gap between the upper layer and glass. The second layer is a sharp corner U-shaped compartment with sharp corners at the fore-end. And another type capture structure with Y-shaped fluidic guide has been designed. It was demonstrated that the structures can capture cells in theory, using Darcy-Weisbach equation and COMSOL Multiphysics. Then yeast cell was chosen to test the performance of the chips. The chip without fluid guides captured ~1.44×10⁵ cells and the capture efficiency was up to 71%. And the chip with fluid guides captured ~ 5.0×10⁴ cells and the capture efficiency was ~ 25%. The chip without fluid guides can capture more cells because the yeast cells in the chip without fluid guides are subject to larger hydrodynamic drag force.

 Microfluidic chips for cells capture using 3-D hydrodynamic structure array.pdf