Liu Ke, Tian Yu, Burrows Sean M, Reif Randall D, Pappas Dimitri
Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, United States.
Anal Chim Acta. 2009 Sep 28;651(1):85-90. doi: 10.1016/j.aca.2009.08.007. Epub 2009 Aug 15.
The ability to quickly measure flow parameters in microfluidic devices is critical for micro total analysis system (microTAS) applications. Macrofluidic methods to assess flow suffer from limitations that have made conventional methods unsuitable for the flow behavior profiling. Single molecule fluorescence correlation spectroscopy (FCS) has been employed in our study to characterize the fluidic vortex generating at a T-shape junction of microscale channels. Due to its high spatial and temporal resolution, the corresponding magnitudes relative to different flow rates in the main channel can be quantitatively differentiated using flow time (tau(F)) measurements of dye molecules traversing the detection volume in buffer solution. Despite the parabolic flow in the channel upstream, a heterogeneous distribution of flow has been detected across the channel intersection. In addition, our current observations also confirmed the aspect of vortex-shaped flow in low-shear design that was developed previously for cell culture. This approach not only overcomes many technical barriers for examining hydrodynamic vortices and movements in miniature structures without physically integrating any probes, but it is also especially useful for the hydrodynamic studies in polymer-glass based micro-reactor and -mixer.
快速测量微流控设备中的流动参数的能力对于微全分析系统（microTAS）应用至关重要。用于评估流动的宏观流体方法存在局限性，使得传统方法不适用于流动行为分析。在我们的研究中，已采用单分子荧光相关光谱法（FCS）来表征在微尺度通道的T形交汇处产生的流体涡旋。由于其高空间和时间分辨率，通过测量染料分子在缓冲溶液中穿过检测体积的流动时间（tau(F)），可以定量区分相对于主通道中不同流速的相应大小。尽管通道上游存在抛物线形流动，但在通道交汇处已检测到流动的不均匀分布。此外，我们目前的观察结果还证实了先前为细胞培养开发的低剪切设计中涡旋形流动的情况。这种方法不仅克服了在不物理集成任何探针的情况下检查微型结构中的流体动力学涡旋和运动的许多技术障碍，而且对于基于聚合物-玻璃的微反应器和微混合器中的流体动力学研究也特别有用。
