Device for Rapid and Agile Measurement of Diffusivity in Micro- and Nanochannels
Device for Rapid and Agile Measurement of Diffusivity in Micro- and Nanochannels
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DOI：
10.1021/ac1033648
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发表时间：
2011-04-15
影响因子：
7.4
通讯作者：
Ferrari, Mauro
中科院分区：
文献类型：
--
作者：
Grattoni, Alessandro;Gill, Jaskaran;Ferrari, Mauro
‘缺乏一个可行的理论来描述当流体被限制在微米和纳米尺度时的扩散性(Ladero等人)。化学。英语。SCI。2007，62,666-678；Deen AIChe J.1987，33,1409-1425]需要准确测量扩散系数(D)Din和Chen Chromatgraph 2000，52，17-21；Nie等人。《科学》1994,266,1018-1021；杜兰德等人。肛门。陈。2009，81,5407-5412]，对许多微和纳米流体技术至关重要[Grattoni等人。货币。药。生物技术。2010，11,343-365]。我们展示了一种快速而灵活的方法来直接测量系统中的扩散率，该系统具有10(4)到10(5)个特征尺寸(β)从微米到纳米的精确制造的通道。定制小室使我们能够使用UV/VIS光谱在封闭的不受干扰的系统中测量扩散系数。在200微米和1微米，以及13和5.7 nm的水溶液中测量了罗丹明B(RhoB)的D。观测到的扩散系数与β的对数比例与先前的实验非常一致，但与理论预测相去甚远，令人惊讶的是，即使在微观尺度上，扩散系数也发生了显著的变化。通过将源水库的规模减小3个数量级(从150亩L减少到910NL)来精确测量D，证明可以实现测量时间的大幅缩短(从7天减少到40分钟)。因此，我们的设计可以快速转换为标准分析工具--适用于多种应用。
'The lack of a viable theory for describing diffusivity when fluids are confined at the micro- and nanoscale [Ladero et al. Chem. Eng. Sci. 2007, 62, 666-678; Deen AIChE J. 1987, 33, 1409-1425] has necessitated accurate measurement of diffusivity (D) Din and Chen Chromatographia 2000, 52, 17-21; Nie et al. Science 1994, 266, 1018-1021; Durand et al. Anal. Chan. 2009, 81, 5407-5412], crucial for a host of micro- and nanofluidic technologies [Grattoni et al. Curr. Pharm. Biotechnol. 2010, 11, 343-365]. We demonstrate a rapid and agile method for the direct measurement of diffusivity in a system possessing 10(4) to 10(5) precisely fabricated channels with characteristic sizes (beta) ranging from micro- to nanometers. Custom chambers allowed us to measure the diffusivity in a closed unperturbed system using UV/vis spectroscopy. D was measured for rhodamine B (RhoB) in aqueous solution in channels of 200 and 1 mu m, as well as 13 and 5.7 nm. The observed logarithmic scaling of diffusivity with beta, in close agreement with prior experiments, but far from theoretical prediction, surprisingly highlights that diffusivity is significantly altered even at the microscale. Accurate measurement of D by reducing the size of the source reservoir by 3 orders of magnitude (from 150 mu L to 910 nL) proves that a substantial reduction in measurement time (from 7 days to 40 min) can be achieved. Our design thus is ready for rapid translation into a standard analytical tool - useful for multiple applications.