Department of Electronic and Computer Engineering and ‡Division of Biomedical Engineering, The Hong Kong University of Science and Technology , Clear Water Bay, Hong Kong SAR, China.
Anal Chem. 2016 Dec 6;88(23):11601-11608. doi: 10.1021/acs.analchem.6b03094. Epub 2016 Nov 15.
This study presents pressure-driven chromatographic separation characteristics of integrated nanofluidic channels (nanocapillaries) featuring distinct cross-sectional geometries: cylindrical, triangular, and rectangular profiles. Cylindrical and triangular nanocapillaries are self-enclosed robust conduits realized through standard semiconductor processing techniques using low-resolution photolithography. Specifically, capillaries in nominal radius 300 and 500 nm have been investigated for chromatographic separation in comparison to 750 nm deep nanoslits as well as triangular capillaries featuring an inscribed circle about 500 nm in radius. Chromatograms have been obtained from 10 mm long nanocapillaries under various modes: normal- and reversed-phase, ion-valence, and hydrodynamic chromatography. The van Deemter plots based on the linear mobile phase velocity for 300 nm radius capillaries and 750 nm deep slits show excellent agreement with the plate heights theoretically predicted. The minimum plate heights achieved are typically below 2 μm and the theoretical plate numbers are in the order of 10 plates/m for the most chromatography modes investigated in the pressure range up to 100 psi. A comparatively high resolving power is achieved with cylindrical nanocapillaries especially those 300 nm in radius. Self-enclosed robust nanocapillaries demonstrated here could facilitate a pressure-driven chromatographic analysis of extremely low-volume samples (e.g., single cell).
本研究展示了集成纳米流道（纳米毛细管）的压力驱动色谱分离特性，这些纳米流道具有不同的横截面几何形状：圆柱形、三角形和矩形。圆柱形和三角形纳米毛细管是通过使用低分辨率光刻技术的标准半导体加工技术自封闭的坚固管道。具体而言，已经研究了名义半径为 300nm 和 500nm 的毛细管，以用于与 750nm 深纳米狭缝以及具有约 500nm 半径的内接圆的三角形毛细管进行色谱分离。已经从各种模式下的 10mm 长纳米毛细管中获得了色谱图：正相和反相、离子价和流体动力学色谱。基于线性移动相速度的 van Deemter 图对于 300nm 半径的毛细管和 750nm 深的狭缝显示出与理论上预测的板高非常吻合。在所研究的压力范围内高达 100psi 的大多数色谱模式下，实现的最小板高通常低于 2μm，理论板数约为 10 块/m。圆柱形纳米毛细管，尤其是半径为 300nm 的圆柱形纳米毛细管，实现了较高的分辨率。这里展示的自封闭坚固纳米毛细管可以促进对极低体积样品（例如单个细胞）的压力驱动色谱分析。
