Fundamental studies of nanofluidics: nanopores, nanochannels, and nanopipets.
Fundamental studies of nanofluidics: nanopores, nanochannels, and nanopipets.
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DOI：
10.1021/ac504180h
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发表时间：
2015-01-06
影响因子：
7.4
通讯作者：
Jacobson, Stephen C.
中科院分区：
文献类型：
--
作者：
Haywood, Daniel G.;Saha-Shah, Anumita;Baker, Lane A.;Jacobson, Stephen C.
在过去的二十年里，由于纳米尺度下表现出的独特的传输特性，纳米流体装置中的离子、颗粒和流体传输受到了相当大的关注。1，2现象，如双层重叠，高表面积体积比，表面电荷，离子电流整流，和熵的障碍，可以影响运输和周围的纳米流体结构，因为这些力量的长度尺度和设备的关键尺寸是相似的。微纳米流控技术的进步提供了设计各种定义明确的纳米流体几何形状的能力，以研究这些现象及其对离子和流体传输的影响。将微流体和纳米流体结构集成到芯片实验室设备中可以增加对一系列分析应用有用的功能。3，4这篇评论的重点是最近的进展，在nanofabletics技术以及研究的基本运输nanofluidic设备。纳米孔、纳米通道和纳米移液管是三种常见的纳米流体结构，它们在研究纳米流体传输中具有影响力。由于篇幅限制，我们将本综述的范围限制在这三种结构的研究上，我们主要关注2011年1月至2014年8月之间发表的工作。我们不讨论与碳纳米管，5纳米网，6或纳米线。图1显示了这里讨论的三种纳米流体几何形状的示例。纳米孔通常垂直于基底平面形成，其特征在于临界极限尺寸，该尺寸通过扫描电子显微镜（SEM）、透射电子显微镜（TEM）或电导测量来测量。孔由多种材料制成，例如聚碳酸酯、聚对苯二甲酸乙二醇酯或氮化硅，根据制造技术，可以具有不对称（图1a）或对称（图1b）形状。对称孔是由电子显微镜确定的具有恒定临界尺寸的圆柱形或在孔中心具有临界尺寸的沙漏形。虽然电子显微镜能够测量外部孔隙尺寸，但精确的内部几何形状通常是未知的，并且可能包含两个对称特征之间的不对称性，例如雪茄形孔隙。不对称纳米孔通常具有窄的尖端和宽的基部，其具有沿孔轴沿着的漏斗形几何形状。尖端和基座尺寸通过SEM测量，但精确的孔几何形状通常是未知的。纳米通道通常是指具有对称（图1c）或不对称（图1d）几何形状的平面内结构。取决于制造方法，通道可以在深度、宽度或两者上被限制到纳米级。纳米通道通常在玻璃和聚合物基底中制造，并通过SEM和原子力显微镜（AFM）表征。这些通道的面内性质允许将明确定义的特征集成到更复杂的几何形状中，并且可以设计任何二维（2D）通道架构。纳米移液管是由拉制玻璃或熔融二氧化硅毛细管制成的专用纳米孔（图1e，f）。纳米吸量管的几何形状为圆锥形，临界尖端直径为数十至数百纳米，可以通过电子显微镜测量。与纳米孔和纳米通道不同，纳米移液管可以容易地与位置控制耦合，这允许纳米移液管的尖端定位在特定位置或用于扫描探针显微镜。
Ion, particle, and fluid transport in nanofluidic devices has received considerable attention over the past two decades due to unique transport properties exhibited at the nanoscale. 1, 2 Phenomena such as double layer overlap, high surface-tovolume ratios, surface charge, ion-current rectification, and entropic barriers can influence transport in and around nanofluidic structures because the length scales of these forces and the critical dimensions of the device are similar. Advances in micro-and nanofabrication techniques provide the ability to design a variety of well-defined nanofluidic geometries to study these phenomena and their effects on ion and fluid transport. Integration of micro-and nanofluidic structures into lab-on-achip devices permits increased functionality that is useful for a range of analytical applications. 3, 4 This Review focuses on recent advances in nanofabrication techniques as well as studies of fundamental transport in nanofluidic devices. Nanopores, nanochannels, and nanopipets are three common nanofluidic structures that have been influential in studying nanofluidic transport. Because of space limitations, we have limited the scope of this Review to studies with these three structures, and we focus our attention primarily on work published betweenJanuary 2011 and August 2014. We do not discuss work with carbon nanotubes, 5 nanomeshes, 6 or nanowires. 7 Figure 1 shows examples of the three nanofluidic geometries discussed here. Nanopores are typically formed perpendicular to the plane of a substrate and are characterized by a critical limiting dimension, which is measured by scanning electron microscopy (SEM), transmission electron microscopy (TEM), or conductance measurements. Pores are fabricated in a variety of materials, eg, poly (carbonate), poly (ethylene terephthalate), or silicon nitride, and can have an asymmetric (Figure 1a) or symmetric (Figure 1b) shape, depending on the fabrication technique. Symmetric pores are either cylindrically shaped with a constant critical dimension determined by electron microscopy or hourglass-shaped with a critical dimension at the center of the pore. Although electron microscopy is capable of measuring exterior pore dimensions, the exact inner geometry is often unknown and may contain an asymmetry between two symmetric features, eg, cigar-shaped pores. Asymmetric nanopores typically have a narrow tip and a wide base with a funnel-shaped geometry along the pore axis. Tip and base dimensions are measured by SEM, but the exact pore geometry is often unknown. Nanochannels often refer to inplane structures with either symmetric (Figure 1c) or asymmetric (Figure 1d) geometries. Channels may be confined to the nanoscale in depth, width, or both, depending on the fabrication method. Nanochannels are commonly fabricated in glass and polymer substrates and characterized by SEM and atomic force microscopy (AFM). The in-plane nature of these channels allows the integration of well-defined features into more complex geometries, and any two-dimensional (2D) channel architecture can be designed. Nanopipets are specialized nanopores fabricated from pulled glass or fusedsilica capillaries (Figure 1e, f). The geometry of a nanopipet is conically shaped with a critical tip diameter of tens to hundreds of nanometers, which can be measured by electron microscopy. Unlike nanopores and nanochannels, nanopipets can be easily coupled with position control, which allows the tip of the nanopipets to be positioned in specific locations or used in scanned probe microscopies.
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DOI：
10.1021/la2005612
发表时间：
2011-05-17
期刊：
Langmuir : the ACS journal of surfaces and colloids
影响因子：
--
作者：
Actis P;Vilozny B;Seger RA;Li X;Jejelowo O;Rinaudo M;Pourmand N
通讯作者：
Pourmand N
影响因子：
2.4
作者：
Chakraborty, Jeevanjyoti;Dey, Ranabir;Chakraborty, Suman
通讯作者：
Chakraborty, Suman
影响因子：
17.1
作者：
Actis, Paolo;Tokar, Sergiy;Korchev, Yuri E.
通讯作者：
Korchev, Yuri E.
带电锥形纳米孔中浓度梯度相关的离子电流整流
影响因子：
3.9
作者：
Cao, Liuxuan;Guo, Wei;Jiang, Lei
通讯作者：
Jiang, Lei
影响因子：
4
作者：
Ali, Mubarak;Ramirez, Patricio;Mafe, Salvador
通讯作者：
Mafe, Salvador