Ultrasensitive surface-enhanced Raman scattering flow detector using hydrodynamic focusing.
Ultrasensitive surface-enhanced Raman scattering flow detector using hydrodynamic focusing.
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DOI：
10.1021/ac401537k
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发表时间：
2013-11-05
影响因子：
7.4
通讯作者：
Schultz, Zachary D.
中科院分区：
文献类型：
--
作者：
Negri, Pierre;Jacobs, Kevin T.;Dada, Oluwatosin O.;Schultz, Zachary D.
流动中无标签、化学特异性检测对于流动注射分析、电泳和色谱等应用中分析物的高通量表征非常重要。我们开发了一种表面增强拉曼散射（SERS）流量检测器，能够在毫秒时间尺度上进行超灵敏的光学检测。该装置采用流体动力学聚焦来改善流道中的SERS检测，其中鞘层流动限制了从平面SERS活性衬底上熔融二氧化硅毛细管洗脱的分析物分子。增加分析物与SERS底物的相互作用显著提高检测灵敏度。采用有限元模拟、荧光成像和拉曼实验相结合的方法研究了该流量检测器的性能。采用基于有限元分析的计算流体力学方法对流动条件进行优化。建模表明，许多因素，如毛细管尺寸和护套流量与分析物流量的比例，对于获得最佳结果至关重要。利用罗丹明6G （R6G）的宽场荧光成像证实了由流动动力学引起的样品约束。与模型预测相比，不同鞘层流速下的拉曼实验显示敏感性增加，表明吸附增加。在50毫秒采集时间、180 μL/min的鞘层流速和5 μL/min的样品流速下，观察到R6G浓度从纳摩尔浓度到微摩尔浓度的线性动态范围，LOD为1 nM。在低分析物浓度下，观察到快速的分析物解吸，从而实现重复和高通量的SERS检测。与传统的基于sers的分析相比，流量检测器提供了实质性的优势，例如最小的样本量和高检测效率。
Label-free, chemical specific detection in flow is important for high throughput characterization of analytes in applications such as flow injection analysis, electrophoresis, and chromatography. We have developed a surface-enhanced Raman scattering (SERS) flow detector capable of ultrasensitive optical detection on the millisecond time scale. The device employs hydrodynamic focusing to improve SERS detection in a flow channel where a sheath flow confines analyte molecules eluted from a fused silica capillary over a planar SERS-active substrate. Increased analyte interactions with the SERS substrate significantly improve detection sensitivity. The performance of this flow detector was investigated using a combination of finite element simulations, fluorescence imaging, and Raman experiments. Computational fluid dynamics based on finite element analysis was used to optimize the flow conditions. The modeling indicates that a number of factors, such as the capillary dimensions and the ratio of the sheath flow to analyte flow rates, are critical for obtaining optimal results. Sample confinement resulting from the flow dynamics was confirmed using wide-field fluorescence imaging of rhodamine 6G (R6G). Raman experiments at different sheath flow rates showed increased sensitivity compared with the modeling predictions, suggesting increased adsorption. Using a 50-millisecond acquisitions, a sheath flow rate of 180 μL/min, and a sample flow rate of 5 μL/min, a linear dynamic range from nanomolar to micromolar concentrations of R6G with a LOD of 1 nM is observed. At low analyte concentrations, rapid analyte desorption is observed, enabling repeated and high-throughput SERS detection. The flow detector offers substantial advantages over conventional SERS-based assays such as minimal sample volumes and high detection efficiency.
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DOI：
10.1039/c1an15432j
发表时间：
2011-11-07
期刊：
The Analyst
影响因子：
--
作者：
Asiala SM;Schultz ZD
通讯作者：
Schultz ZD
影响因子：
7.4
作者：
Liu, Jikun;White, Ian;DeVoe, Don L.
通讯作者：
DeVoe, Don L.
影响因子：
7.4
作者：
Hofmann, O;Voirin, G;Manz, A
通讯作者：
Manz, A
影响因子：
6.1
作者：
Choi, Inhee;Huh, Yun Suk;Erickson, David
通讯作者：
Erickson, David
影响因子：
3.5
作者：
KNEIPP, K;WANG, Y;FELD, MS
通讯作者：
FELD, MS