磁富集微流控光纤表面增强拉曼散射探针的拉曼增强特性  

Raman Enhancement Characteristics of Magnetically Enriched Microfluidic Optical Fiber Surface-Enhanced Raman Scattering Probes

作　　者：甘愿 黄博 孙宁 张洁[1] Gan Yuan;Huang Bo;Sun Ning;Zhang Jie(Key Laboratory of Optoelectronic Technology&System,Ministry of Education,College of Optoelectronic Engineering,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学光电工程学院光电技术及系统教育部重点实验室,重庆400044

出　　处：《光学学报》2024年第23期252-260,共9页Acta Optica Sinica

基　　金：国家自然科学基金(62175023)。

摘　　要：为了提升拉曼检测系统的灵敏度、集成度和实用性,本文提出了一种基于磁富集效应的多路微流控集成D型光纤表面增强拉曼散射(SERS)探针。首先,通过一步还原法制备了形貌均一的银纳米颗粒(Ag NPs),再利用静电吸附法将其吸附于Fe_(3)O_(4)微球表面,形成Fe_(3)O_(4)@Ag NPs复合结构;其次,利用自行设计的多路微流控模板制备了微流控聚二甲基硅氧烷(PDMS)通道;最后,将D型光纤和多路微流控通道及载玻片进行键合,随后将制备好的Fe_(3)O_(4)@Ag NPs注入微通道中,在磁铁的静磁场作用下将其富集在D型光纤平面区域,得到微流控D型光纤SERS探针。本文所制备的样品对罗丹明染料(R6G)表现出良好的探测性能(检测极限低至10^(-8)mol/L,增强因子为2.88×10^(6))。此外,该样品能够同时对多分子进行检测,并具备优异的可重复性和实用性。Objective Surface-enhanced Raman scattering(SERS)is a vibrational spectroscopy technique that amplifies molecular Raman signals using precious metal nanostructures.Recently,SERS has emerged as a powerful fingerprint identification tool for rapid,non-destructive,and ultra-sensitive detection of various chemical and biological targets,with broad applications in analysis and sensing.To further improve the sensitivity,integration,and practicality of the Raman detection system,we propose a multi-channel microfluidic D-shaped fiber SERS probe based on magnetic enrichment.Methods First,uniformly shaped silver nanoparticles(AgNPs)are prepared using a one-step reduction method and then adsorbed onto Fe3O4 microbeads through electrostatic interactions to form a Fe3O4@AgNPs composite structure.Next,microfluidic channels are created,using a custom-designed polydimethylsiloxane(PDMS)template.The D-shaped fiber,microfluidic channels,and a glass slide are bonded together,and the prepared Fe3O4@AgNPs are injected into the microchannels.Under the influence of a magnetic field,the nanoparticles are enriched in the planar region of the D-shaped fiber,forming a microfluidic D-shaped fiber SERS probe.To further analyze the enhancement mechanism of the D-shaped fiber SERS probe,we utilize COMSOL Multiphysics software for simulation.The model parameters include a cladding radius(R)of 62.5μm,a core radius(r)of 31.25μm,a core refractive index(n1)of 1.46,and a cladding refractive index(n2)of 1.44.Simulation results indicate a theoretical maximum enhancement factor(EF)of approximately 6.2×104.Results and Discussions To experimentally verify the magnetic enrichment effect,we conduct a series of comparative experiments.First,we prepare R6G solutions with concentrations of 10^(−7),10^(−8),and 10^(−9) mol/L,and sequentially introduce the prepared composite structures into 3 mL of these R6G solutions.After thoroughly mixing the composites with the test solutions,50μL of the mixture is pipetted onto a silicon wafer.Magnetic aggregation

关 键 词：表面增强拉曼散射 微流控 磁富集 D型光纤 

分 类 号：O436[机械工程—光学工程]