一种用于常规和表面增强拉曼光谱的微流控系统中的可调谐自由曲面分段反射镜。

A Tunable Freeform-Segmented Reflector in a Microfluidic System for Conventional and Surface-Enhanced Raman Spectroscopy.

机构信息

Department of Applied Physics and Photonics, Brussels Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, B-1050 Brussels, Belgium.

Department of Micro- and Nanotechnology, Technical University of Denmark, Ørsteds Plads, Building 345 east, 2800 Kgs. Lyngby, Denmark.

出版信息

Sensors (Basel). 2020 Feb 25;20(5):1250. doi: 10.3390/s20051250.

DOI:10.3390/s20051250

PMID:32106463

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC7085544/

Abstract

We present a freeform-segmented reflector-based microfluidic system for conventional Raman and Surface-Enhanced Raman Scattering (SERS) analysis. The segmented reflector is directly designed by a numerical approach. The polymer-based Raman system strongly suppresses the undesirable background because it enables confocal detection of Raman scattering through the combination of a freeform reflector and a microfluidic chip. We perform systematic simulations using non-sequential ray tracing with the Henyey-Greenstein model to assess the Raman scattering behavior of the substance under test. We fabricate the freeform reflector and the microfluidic chip by means of ultra-precision diamond turning and laser cutting respectively. We demonstrate the confocal behavior by measuring the Raman spectrum of ethanol. Besides, we calibrate the setup by performing Raman measurements on urea and potassium nitrate solutions with different concentrations. The detection limit of our microfluidic system is approximately 20 mM according to the experiment. Finally, we implement a SERS microfluidic chip and discriminate 100 µM urea and potassium nitrate solutions.

摘要

我们提出了一种基于自由曲面反射镜的微流控系统，用于常规拉曼和表面增强拉曼散射（SERS）分析。分段反射镜是通过数值方法直接设计的。基于聚合物的拉曼系统由于能够通过自由曲面反射镜和微流控芯片的组合实现拉曼散射的共焦检测，因此可以强烈抑制不想要的背景。我们使用非序列光线追踪和 Henyey-Greenstein 模型进行系统模拟，以评估测试物质的拉曼散射行为。我们分别通过超精密金刚石车削和激光切割来制造自由曲面反射镜和微流控芯片。我们通过测量乙醇的拉曼光谱来证明共焦行为。此外，我们通过对不同浓度的尿素和硝酸钾溶液进行拉曼测量来校准该装置。根据实验，我们的微流控系统的检测限约为 20mM。最后，我们实现了一个 SERS 微流控芯片，并区分了 100µM 尿素和硝酸钾溶液。