磁性复合材料在表面增强拉曼光谱中的应用

表面增强拉曼散射(SERS)光谱具有灵敏度高、检测速度快及选择性好等优点。近年来SERS光谱被广泛地应用于分析化学、环境科学、生物传感和界面催化等领域。SERS基底的性能是SERS技术能否得到广泛应用的关键问题。磁性-等离子体纳米复合材料具有SERS活性高、磁分离速度快和稳定性高的特点,已成为材料研究领域的热点之一。从食品安全、环境保护、生物传感与医学诊断、有机污染物的光催化降解及反应监测、药品质量检测五个方面出发,综述了近年来磁性-等离子体纳米复合材料在SERS检测中的应用,对目前磁性-等离子体纳米复合材料作为SERS基底的应用所存在的问题进行了讨论,并展望了未来的研究发展方向。     

基于SERS探针技术的细胞识别、成像与诊疗

表面增强拉曼散射(surface-enhanced Raman scattering, SERS),是指吸附在粗糙的金属纳米结构表面的被分析物,在光照射下其拉曼光谱获得显著增强的异常表面光学现象。近年来,SERS技术已广泛地用于物质检测和生物传感等研究,在生物医学领域表现出巨大的应用潜力并取得了令人瞩目的研究成果。本文回顾了SERS探针技术在细胞识别、成像与诊疗等方面的应用及最新研究进展,重点介绍了SERS细胞探针的构建方法与原理,以及基于SERS探针的细胞检测应用策略,并讨论了SERS探针技术在细胞检测中仍有待解决的关键问题。     

组蛋白乙酰化的耦合增强拉曼散射生物传感方法

提出了一种组蛋白乙酰化修饰检测的耦合增强拉曼散射生物传感新方法. 该方法以金纳米粒子为表面增强拉曼散射(SERS)基底, 表面修饰乙酰化组蛋白H3多肽为识别探针, 对甲氧基苯硫酚(4-MTP)为拉曼标记物, 制备了组蛋白乙酰化修饰检测的SERS纳米探针. 通过紫外可见吸收光谱与动态光散射分析, 证实了组蛋白乙酰化抗体可介导SERS纳米粒子发生可控组装与聚集, 使SERS纳米探针间发生局域电场共振耦合, 产生显著增强的SERS信号. 基于此, 通过待测抗原与SERS纳米探针对抗体的竞争性相互作用, 我们设计了组蛋白乙酰化修饰检测的竞争免疫SERS生物传感方法. 该法操作简便、快速、重现性好, 且裸眼即能进行可视化鉴定. 通过设计不同染料标记的SERS纳米探针, 该法有望实现多种组蛋白修饰的复合检测.     

表面增强拉曼散射技术在生物传感与成像分析中的应用

表面增强拉曼散射(Surface-enhanced Raman scattering, SERS)技术是一种具有原位无损、指纹信息识别和单分子水平检测能力的光谱分析手段,在食品安全、环境监测和生物分析等领域具有良好的应用价值和潜力。本文综述了近年来SERS技术在生物传感与成像分析领域中的研究现状,展望了其未来发展趋势和应用前景。     

金纳米棒:合成、修饰、自组装、SERS及生物医学应用

纳米颗粒作为信号感应单元在化学与生物传感应用中已引起广泛关注,这些功能和金属纳米结构与光相互作用时产生的表面等离子体共振密切相关.表面增强拉曼散射(SERS),是指吸附在粗糙的金属纳米结构表面的被分析物,在光照射下其拉曼光谱获得显著增强的异常表面光学现象,近年来.SERS技术已广泛用于物质检测和生物传感等研究,在生物医学领域表现出巨大的应用潜力并取得了令人瞩目的研究成果.本文阐述了金纳米棒的制备方法、表面修饰和共轭生物分子的方法.并从金纳米棒表面增强拉曼散射的角度系统阐述基于金纳米棒表面增强拉曼散射的1D,2D,3D自组装,并介绍了近期金纳米棒表面增强拉曼散射在生物医学检测与成像中最具有代表性的应用研究.     

表面等离子体共振传感技术和生物分析仪

表面等离子体共振（surface plasmon resonance, SPR）传感技术是生物化学分析领域常用的分析手段和研究工具,与其相关的研究不计其数,发展日新月异。本研究小组从事SPR传感技术研究近十年,从初期的理论研究、仿真计算、传感器设计以及全自动SPR生物分析仪开发与应用研究,到目前的传感器性能提高、应用拓展,时刻关注着该项技术的最新动态。本文系统综述了SPR传感技术和生物分析仪的原理、结构以及主要功能模块,SPR传感器的调制类型、耦合方式以及SPR成像传感器;介绍了结合局域表面等离子体共振（local surface plasmon resonance, LSPR）技术、改进金属膜系设计、优化数据处理算法等提高SPR生物分析仪性能的方法;阐述了SPR传感技术和生物分析仪的最新进展,包括SPR技术和微流控芯片、电化学技术、表面增强拉曼散射技术（SERS）的联用;列举了SPR生物分析仪在临床诊断、药物筛选、生物分子研究、食品安全和环境监测等领域的应用实例;最后,分析了SPR生物分析仪面临的主要问题以及未来的发展趋势。     

SERS标记纳米粒子用于免疫识别

激光拉曼光谱技术近年来已成为研究生物分子结构常用的光谱手段.尤其在研究水溶液中蛋白质的结构和构象方面发挥了重要作用.然而,常规拉曼光谱的信号强度很低,限制了其在各个领域中的应用.表面增强拉曼光谱(SERS)和表面增强共振拉曼光谱(SERRS)技术可使信号增强6～10个数量级,尤其是SERS技术已发展到检测单分子的水平,更为其在生物方面的应用开拓了新的局.     

等离子体金属纳米结构在SERS传感及可穿戴应力传感中的应用

等离子体金属(金、银)纳米结构因其特有的理化性能,被广泛应用于表面增强拉曼散射(Surface-enhanced Raman scattering,SERS)传感及可穿戴应力传感领域.其中,SERS是一种应用贵金属纳米材料增强拉曼散射信号的检测技术,该技术灵敏度高、特异性强,已被广泛用于生物医学、环境监测、食品药品检测...     

等离激元激励表面增强拉曼光谱检测技术与仪器

本文总结了近年来基于传播型表面等离激元（Propagafingsurfaceplasmons,PSPs）参与的表面增强拉曼（Surface—enhancedRamanscattering,SERS）技术和仪器方面的研究进展．内容主要包括3部分：（1）基于PSPs激励拉曼散射的装置和技术,包括在消逝场下激发PSPs共振增强拉曼的原理与装置、与表面等离子体共振（Surfaceplasmonresonance,SPR）传感技术的联用及新型结构的长程等离激元激励拉曼技术的研究进展;（2）通过引入局域型表面等离激元（Localizedsurfaceplasmons,LSPs）进一步增强SERS,进而实现PSPs-LSPs共同增强拉曼的超灵敏检测技术,包括在消逝场激发的PSPs基础上,增加纳米粒子实现的PSPs与LSPs共同增强拉曼的原理、装置,以及用该方法进行生物体系的免疫识别检测,此外,还在微纳周期结构上实现了PSPs与LSPs共同激励拉曼;（3）基于PSPs耦合的定向SERS技术,包括在消逝场结构和周期结构上实现SERS定向耦合发射以达到高激发和高收集效率的新技术．     

细胞功能分子的表面增强拉曼成像及其应用研究进展

表面增强拉曼光谱(surface-enhanced Raman spectroscopy, SERS)具有高灵敏、高通量的特性.基于SERS的拉曼成像技术是一种无损的生物成像技术,已被广泛应用于细胞表面与细胞内生物分子的检测和成像,如对聚糖、microRNA、蛋白质等分子的定量、结构分析与功能追踪等.这一技术也已用于细菌的快速检测、细胞或细菌间的信号通讯研究、细胞p H检测,并可通过活体肿瘤组织的边缘描绘指导手术切除. SERS成像可以规避生命体系中强的分子自荧光以及荧光成像中的光漂白现象,并可以利用不同拉曼信标的指纹光谱实现高灵敏、高通量的生物成像.通过与其他成像技术(如核磁共振成像、光声成像)的结合, SERS成像有望用于更复杂生命体系中生物分子的研究.本文综述了近年来细胞功能分子的表面增强拉曼成像及其应用方面的研究进展.     

Optical fibre SERS sensors

Surface-enhanced Raman scattering (SERS) has established itself as an important analytical technique. However, efforts to transfer the technology from the laboratory to the production line, clinic or field have been frustrated by the lack of robust affordable substrates and the complexity of interfacing between sample and spectrometer. Prompted by the success of optical fibre systems for implementing normal Raman scattering spectroscopy in remote locations and biomedical applications, attention has now shifted to the development of SERS-active optical fibres. Other workers have attempted to develop SERS probes with extended interaction lengths and both far-field and near-field SERS imaging techniques for high-resolution chemical mapping of surfaces. This review discusses the development of these technologies and presents the current state of the art. Although recent developments show great promise, some outstanding challenges and opportunities remain to be addressed.     

SERS in Salt Wells

We report herein a simple, inexpensive fabrication methodology of salt microwells, and define the utility of the latter as nanoparticle containers for highly sensitive surface‐enhanced Raman scattering (SERS) studies. AFM characterization of Ag and Au loaded salt microwells reveal the ability to contain favorable nanostructures such as nanoparticle dimers, which can significantly enhance the Raman intensity of molecules. By performing diffraction‐limited confocal Raman microscopy on salt microwells, we show high sensitivity and fidelity in the detection of dyes, peptides, and proteins, as a proof of our concept. The SERS limit of detection (accumulation time of 1 s) for rhodamine B and TAT contained in salt mircowells is 10 pM and 1 nM , respectively. The Raman characterization measurements of salt microwells with three different laser lines (532 nm, 632.81 nm, 785 nm) reveal low background intensity and high signal‐to‐noise ratio upon nanoparticle loading, which makes them suitable for enhanced Raman detection. SERS mapping of these sub‐femtoliter containers show spatial confinement of the relevant analyte to a few microns, which make them potential candidates for microscale bioreactors.     

SERS spectroscopy and SERS imaging of Shewanella oneidensis using silver nanoparticles and nanowires

Facile and reproducible SERS signals from Shewanella oneidensis were obtained utilizing silver nanoparticles (AgNPs) and silver nanowires (AgNWs). Additionally, SERS images identify the distribution of SERS hot-spots. One important observation is the synergistically enhanced SERS signal when AgNPs and AgNWs are used in conjunction, due to constructively enhanced electromagnetic field.     

In situ dynamic measurements of the enhanced SERS signal using an optoelectrofluidic SERS platform

A novel active surface-enhanced Raman scattering (SERS) platform for dynamic on-demand generation of SERS active sites based on optoelectrofluidics is presented in this paper. When a laser source is projected into a sample solution containing metal nanoparticles in an optoelectrofluidic device and an alternating current (ac) electric field is applied, the metal nanoparticles are spontaneously concentrated and assembled within the laser spot, form SERS-active sites, and enhance the Raman signal significantly, allowing dynamic and more sensitive SERS detection. In this simple platform, in which a glass slide-like optoelectrofluidic device is integrated into a conventional SERS detection system, both dynamic concentration of metal nanoparticles and in situ detection of SERS signal are simultaneously possible with only a single laser source. This optoelectrofluidic SERS spectroscopy allows on-demand generation of 'hot spots' at specific regions of interest, and highly sensitive, reliable, and stable SERS measurements of the target molecules in a tiny volume (～500 nL) of liquid sample without any fluidic components and complicated systems.     

Bottom-up optimization of SERS hot-spots

The bottom-up optimization of signal-to-noise ratios for SERS tags employing SAMSA fluorescein as the reporter was achieved using a bifunctional linker with low Raman cross section. By holding the nanoparticles at subnanometer separation, the linker allowed us to optimize the hot-spot thereby significantly reducing the fluorescence background.     

Defect engineering in semiconductor-based SERS

Semiconductor-based surface enhanced Raman spectroscopy (SERS) platforms take advantage of the multifaceted tunability of semiconductor materials to realize specialized sensing demands in a wide range of applications. However, until quite recently, semiconductor-based SERS materials have generally exhibited low activity compared to conventional noble metal substrates, with enhancement factors (EF) typically reaching 10³, confining the study of semiconductor-based SERS to purely academic settings. In recent years, defect engineering has been proposed to effectively improve the SERS activity of semiconductor materials. Defective semiconductors can now achieve noble-metal-comparable SERS enhancement and exceedingly low, nano-molar detection concentrations towards certain molecules. The reason for such success is that defect engineering effectively harnesses the complex enhancement mechanisms behind the SERS phenomenon by purposefully tailoring many physicochemical parameters of semiconductors. In this perspective, we introduce the main defect engineering approaches used in SERS-activation, and discuss in depth the electromagnetic and chemical enhancement mechanisms (EM and CM, respectively) that are influenced by these defect engineering methods. We also introduce the applications that have been reported for defective semiconductor-based SERS platforms. With this perspective we aim to meet the imperative demand for a summary on the recent developments of SERS material design based on defect engineering of semiconductors, and highlight the attractive research and application prospects for semiconductor-based SERS.

Defect engineering strategies are used to boost the SERS activity of a wide variety of semiconductors including metal oxides, nitrides, carbon materials and transition metal dichalcogenides (TMDs), as discussed in this perspective.     

Recent progress in SERS biosensing

This perspective gives an overview of recent developments in surface-enhanced Raman scattering (SERS) for biosensing. We focus this review on SERS papers published in the last 10 years and to specific applications of detecting biological analytes. Both intrinsic and extrinsic SERS biosensing schemes have been employed to detect and identify small molecules, nucleic acids, lipids, peptides, and proteins, as well as for in vivo and cellular sensing. Current SERS substrate technologies along with a series of advancements in surface chemistry, sample preparation, intrinsic/extrinsic signal transduction schemes, and tip-enhanced Raman spectroscopy are discussed. The progress covered herein shows great promise for widespread adoption of SERS biosensing.     

Highly efficient SERS test strips

We present a facile production approach to highly efficient SERS test strips by physical vapor deposition of silver on paper, which contains natural wrinkle and fibril structures. The SERS test strips open the door to highly sensitive (e.g., 10(-10) M) SERS detection in a convenient fashion.     

Bi-analyte SERS with isotopically edited dyes

Isotopically substituted rhodamine dyes provide ideal probes for the study of single-molecule surface enhanced Raman scattering (SM-SERS) events through multiple-analyte techniques. Isotopic editing should, in principle, provide probes that have identical chemical properties (and surface chemistries); while exhibiting at the same time distinct Raman features which enable us to identify single-molecule SERS events. We present here a specific example of two-analyte SM-SERS based on the isotopic substitution of a methyl ester rhodamine dye. The dyes are carefully characterized (in both standard and SERS conditions) to confirm experimentally their similar chemical properties. We then demonstrate their utility for bi-analyte SERS (BiASERS) experiments and, as an example, highlight the transition from a single, to a few, to many molecules in the statistics of SM-SERS signals.