An optimal three-dimensional focusing technique for micro-flow cytometers
An optimal three-dimensional focusing technique for micro-flow cytometers
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DOI：
10.1007/s10404-008-0284-6
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发表时间：
2008-04
影响因子：
2.8
通讯作者：
C. Tsai;H. Hou;Lung-Ming Fu
中科院分区：
文献类型：
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作者：
C. Tsai;H. Hou;Lung-Ming Fu
本研究提出了一种新的三维（3-D）流体动力学聚焦技术的微流式细胞仪。在所提出的方法中，样品流最初在水平方向上被两个鞘流压缩，使得它被约束在微通道的中心区域。然后，样品流通过第二对鞘流在垂直方向上聚焦，随后通过位于光学检测系统正下方的微堰结构。微通道的配置和操作参数进行了优化，通过执行一系列的数值模拟，以检查上的样品流分布的垂直和水平的聚焦比，第二套鞘流通道的入口角，和第二套鞘流通道的宽度和深度的影响。结果表明，水平和垂直鞘流成功地限制在一个狭窄的，明确界定的区域内的微通道的样品流。此外，微堰结构导致细胞/颗粒在垂直方向上的分离，并确保它们以顺序的方式流过微通道的检测区域，因此可以可靠地计数。结果表明，在适当的水平聚焦比下，三维聚焦技术可以获得6 ~ 15 μm的聚焦样品流宽度。因此，确认了用于计数和检测单个生物细胞的微流式细胞仪的活力。
This study presents a novel three-dimensional (3-D) hydrodynamic focusing technique for micro-flow cytometers. In the proposed approach, the sample stream is initially compressed in the horizontal direction by two sheath flows such that it is constrained in the central region of the microchannel. The sample stream is then focused in the vertical direction by a second pair of sheath flows and subsequently passes over a micro-weir structure positioned directly beneath an optical detection system. The microchannel configuration and operational parameters are optimized by performing a series of numerical simulations to examine the effects on the sample stream distribution of the vertical and horizontal focusing ratios, the entrance angle of the second set of sheath flow channels, and the width and depth of the second set of sheath flow channels. The results indicate that the horizontal and vertical sheath flows successfully constrain the sample stream within a narrow, well-defined region of the microchannel. Furthermore, the micro-weir structure results in the separation of the cells/particles in the vertical direction and ensures that they flow in a sequential fashion through the detection region of the microchannel and can therefore be reliably counted. It is shown that the 3-D focusing technique can achieve a focused sample stream width of between 6 and 15 μm given an appropriate value of the horizontal focusing ratio. Thus, the viability of the microflow cytometer for the counting and detection of individual biological cells is confirmed.