Behavior of capillary valves in centrifugal microfluidic devices prepared by three-dimensional printing
Behavior of capillary valves in centrifugal microfluidic devices prepared by three-dimensional printing
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DOI：
10.1007/s10404-010-0721-1
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发表时间：
2011-04-01
影响因子：
2.8
通讯作者：
Johnson, R. Daniel
中科院分区：
文献类型：
--
作者：
Moore, Jessica L.;McCuiston, Austin;Johnson, R. Daniel
本文详细介绍了通过三维（3D）或固体物体打印制备的离心微流体装置中的毛细管阀的行为。微流体结构包含不同的宽度，高度和径向距离的旋转中心的阀门通道进行了研究，并与现存的毛细管阀理论进行了比较。由于印刷工艺，所生产的阀通道具有脊状或“扇形”图案。因此，确定了脊状图案最宽和最窄点处的实际通道宽度，并将其用于理论值与经验值之间的比较。此外，在接触角的变化导致的脊图案进行了测量，并在理论计算中使用。对于1毫米高的阀门通道，克服毛细管阀压力所需的临界角频率（rpm）被发现是独立的宽度。然而，随着阀通道的高度减小，发现临界rpm变得越来越依赖于宽度，对于较窄的通道，临界rpm增加得更快。这两个观察结果都指出了特征锐度以及瓣膜通道开口的几何形状在瓣膜行为中的作用。否则，阀门遵循一个可预测的趋势，即随着阀门高度的降低和与旋转中心的径向距离的减小，临界转速增加。然后，使用这些结果作为指导，可以通过3D打印制备离心微流体装置，其可操作性与通过其他微制造技术制备的装置相当。
This paper details the behavior of capillary valves in centrifugal microfluidic devices prepared by three-dimensional (3D), or solid-object, printing. Microfluidic structures containing valve channels with different widths, heights, and radial distances from the center of rotation were studied and compared with extant capillary valve theories. Due to the printing process, the produced valve channels possessed a ridged or "scalloped" pattern. Hence, actual channel widths at the widest and narrowest points of the ridged pattern were determined, and used in comparisons between theoretical and empirical values. In addition, variations in contact angle resulting from the ridged pattern were measured and employed in theoretical calculations. For 1-mm high valve channels, the critical angular frequency (rpm) required to overcome capillary valve pressure was found to be independent of width. However, as the height of the valve channel was reduced, the critical rpm was found to become progressively more width-dependent increasing more rapidly for narrower channels. Both of these observations point to a role for feature sharpness, as well as the geometry of the valve channel opening, in valve behavior. Otherwise, valves followed a predictable trend of increasing critical rpm with decreased valve height and decreased radial distance from the rotation center. Using these results as a guide, then, it is possible to prepare centrifugal microfluidic devices by 3D printing with operability comparable to devices prepared by other microfabrication techniques.