Liu Danyang, Liu Chuanyu, Yuan Yuan, Zhang Xin, Huang Yingzhou, Yan Sheng
State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China.
Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China.
Anal Chem. 2021 Aug 3;93(30):10672-10678. doi: 10.1021/acs.analchem.1c02139. Epub 2021 Jul 26.
For its ultrahigh sensitivity, the microfluidic system combined with surface-enhanced Raman spectroscopy (SERS) becomes one of the most interesting topics in integrated online monitoring related fields. In previous reports, the commonest surface plasmon-enhanced substrates in microfluidics consist of immobilized metal nanostructures on the channel surface to overcome the disturbance of Brownian motion. In this work, a hybrid optoplasmonic microfluidic conveyer is developed, in which the movable, highly ordered optoplasmonic particles are delivered to the detection spot for SERS detection. Here, the optoplasmonic particle is the SiO microsphere with in situ photochemical reduced Ag nanoparticles on the surface. Because of the converged light at the SiO microsphere surface, the SERS spectra collected at this optoplasmonic particle in the channel exhibit excellent performance, which is confirmed by the simulated electric field distribution. In addition, the experimental data also demonstrate that the quantitative analysis is achieved at 1 nM in this optoplasmonic microfluidic conveyer. Furthermore, the used optoplasmonic particle can be ejected from the microfluidic channel by modulating the velocity of injected fluid such that the new optoplasmonic particle will be delivered to the detection spot for repeatable SERS detection in the same channel. The dynamic process of optoplasmonic particle transport is investigated in this microconveyer, and the built theoretical model to predict the particle release is highly identical with the experimental data. These data point out that our hybrid optoplasmonic microfluidic conveyer has repeatable enhanced substrates with the high SERS sensitivity to overcome the cross-contamination of different target molecules in repeatable detection.
由于其超高的灵敏度，微流控系统与表面增强拉曼光谱（SERS）相结合，成为集成在线监测相关领域中最受关注的课题之一。在以往的报道中，微流控中最常见的表面等离子体增强基底由固定在通道表面的金属纳米结构组成，以克服布朗运动的干扰。在这项工作中，开发了一种混合光等离子体微流控输送器，其中可移动的、高度有序的光等离子体颗粒被输送到检测点进行SERS检测。这里，光等离子体颗粒是表面具有原位光化学还原银纳米颗粒的SiO微球。由于SiO微球表面的光汇聚，在通道中该光等离子体颗粒处收集的SERS光谱表现出优异的性能，这通过模拟电场分布得到了证实。此外，实验数据还表明，在这种光等离子体微流控输送器中，在1 nM时实现了定量分析。此外，通过调节注入流体的速度，可以将使用过的光等离子体颗粒从微流控通道中排出，从而使新的光等离子体颗粒被输送到检测点，在同一通道中进行可重复的SERS检测。在这种微输送器中研究了光等离子体颗粒传输的动态过程，建立的预测颗粒释放的理论模型与实验数据高度吻合。这些数据表明，我们的混合光等离子体微流控输送器具有可重复的增强基底，具有高SERS灵敏度，可在重复检测中克服不同目标分子的交叉污染。
