Fiber cladding dual channel surface plasmon resonance sensor based on S-type fiber

Fiber cladding surface plasmon resonance(SPR)sensors have few structures,and a clad SPR sensor based on S-type fiber is proposed in this paper.This new type of fiber cladding SPR sensor was formed by electrofusing an S-shaped structure on the fiber to couple the light in the fiber core to the cladding.In this paper,the effects of fiber parameters on the performance of the sensor were studied by simulation and experiment.Based on the conclusion that the smaller the core diameter is,the closer the working band of the SPR resonance is to long wavelengths,and that the geometric characteristics mean that a multimode fiber can receive the fiber cladding light from a small core diameter few-mode fiber,a dual channel SPR sensor with a double S-type fiber cascade was proposed.In the refractive index detection range of 1.333–1.385refractive index units(RIU),the resonant working band of channel I is 627.66 nm–759.78 nm,with an average sensitivity of 2540.77 nm/RIU,and the resonant working band of channel II is 518.24 nm–658.2 nm,with an average sensitivity of2691.54 nm/RIU.The processing method for the S-type fiber cladding SPR sensor is simple,effectively solving the problem of this type of SPR sensor structure and the difficult realization of a dual channel.The sensor is expected to be used in the fields of medical treatment and biological analysis.

Dual-channel fiber-optic surface plasmon resonance sensor with cascaded coaxial dual-waveguide D-type structure and microsphere structure

To address the restriction of fiber-optic surface plasmon resonance(SPR) sensors in the field of multi-sample detection, a novel dual-channel fiber-optic SPR sensor based on the cascade of coaxial dual-waveguide D-type structure and microsphere structure is proposed in this paper. The fiber sidepolishing technique converts the coaxial dual-waveguide fiber into a D-type one, and the evanescent wave in the ring core leaks, generating a D-type sensing region;the fiber optic fused ball push technology converts the coaxial dual waveguides into microspheres, and the stimulated cladding mode evanescent wave leaks, producing the microsphere sensing region. By injecting light into the coaxial dual-waveguide middle core alone, the sensor can realize single-stage sensing in the microsphere sensing area;it can also realize dual-channel sensing in the D-type sensing area and microsphere sensing area by injecting light into the ring core. The refractive index measurement ranges for the two channels are 1.333–1.365 and 1.375–1.405, respectively, with detection sensitivities of 981.56 nm/RIU and 4138 nm/RIU. The sensor combines wavelength division multiplexing and space division multiplexing technologies, presenting a novel research concept for multi-channel fiber SPR sensors.

Surface Plasmon Resonance for C-Reactive Protein Detection in Human Plasma

In this work, we describe an approach of detecting biomarkers by Surface Plasmon Resonance imaging (SPRi) technique in real samples. Two C-Reactive Protein (CRP)-antibody immobilization methods were used: The first method was based on direct physisorption of CRP-antibody onto gold surface;the second one was based on oriented CRP-antibody with protein G intermediate layer. The two developed immunosensors were tested against CRP antigen in phosphate buffer saline solution with the SPRi technique. The response of the developed immunosensors was reproducible and stable. The detection limit of 10 pg&#183mL&#451 and 50 pg&#183mL&#451 CRP-antigen was observed with and without protein G respectively with this technique. Moreover, the developed SPRi immunosensor was used for CRP-antigen detection in human plasma. A detection limit of 5 ng&#183mL&#451 and 10 ng&#183mL&#451 was obtained with and without protein G respectively. These obtained results were compared to those obtained with QCM (Quartz Crystal Microbalance) and Enzyme-Linked Immunosorbent Assay (ELISA) techniques.

Analysis of 17β-Estadiol from Sewage in Coastal Marine Environment by Surface Plasmon Resonance Technique

In this study, surface plasmon resonance （SPR） for monitoring 17β-eatradiol （E2） was developed. The small molecule E2 was immobilized on a CM5 sensor chip for an indirect competitive immunoassay to detect E2. The SPR response bahed on the antigen-antibody reaction was measured by injecting the sample solution into the flow system. The limitation of detection was 0.445 μg/L. The developed SPE-SPR system was applied to analyze the seawater samples. Recovery of E2 was 91.6%-93. 1%. Relative standard deviations（RSD） for the E2 assay were between 10.9%-15.1% （n = 3）. The range of determination of E2 samples from the sewage in the coastal marine environ-ment was between ND（lower than detection limit） and ca. 11.78 ng/L.

Detection of Penicillin via Surface Plasmon Resonance Biosensor

A method of using Au colloid to capture the decomposed product of penicillin, penicillamine, on a surface plasmon resonance（SPR） biosensor for the quantitative determination of penicillin was developed. Based on the de-composition of penicillin to generate penicillamine and penilloaldehyde, a high sensitive biosensor for detecting penicillin was also developed. In our experiment, it was penicillamine rather than penicillin that has been measured. This is because penicillamine contains a functional group that makes it self-assembling on Au colloid to increase the molecular weight so as to improve the surface plasmon resonance signal. On a UV-Vis spectrophotometer, a high concentration of penicilliamine-Au complex was determined, indicating that penicillamine was already well combined with Au colloid. The method, using the combination of Au colloid with penicillamine, proved to detect penicillin.

Advances in Phase Detection Technique of Surface Plasmon Resonance Biosensor

Surface plasmon resonance (SPR) sensing is an optical method based on evanescent wave.SPR biosensor can detect interaction of label-free biomolecules in real-time.With further development,it can become a research instrument in proteomics.SPR biosensor can be divided intensity measurement and phase measurement,and the latter possesses higher sensitivity than the former one.This paper attempts to summarize the SPR phase detection theory,discuss the major developments,compare the merits and deficiencies of various methods,and look forward to future prospects.

Characteristics of Surface Plasmon Resonance Imaging lnterferometer

In recent life science research,identifying and characterizing entire biomolecular interaction networks is prerequisite to understanding cellular processes on a molecular and biophysical level.A surface plasmon resonance (SPR) imaging interferometer based on spatial phase modulation detection is presented to meet this demand.In this method,the SPR sensing chip surface is illuminated with collimated parallel light beam,and a Wollaston prism is introduced into the reflected light path to produce the interference of polarized light reflected from SPR sensing chip.Information of biomolecular interactions can be obtained by extracting the phase change from the SPR interference patterns.Using our interferometer,we made experiments on a series concentration of NaCl solutions to investigate its detection range,linearity,sensitivity and resolution.The results indicate that the SPR imaging interferometer is mainly sufficient for biomolecular interaction detection.

Particle-in-cell investigation on the resonant absorption of a plasma surface wave

The resonant absorption of a plasma surface wave is supposed to be an important and efficient mechanism of power deposition for a surface wave plasma source. In this paper, by using the particle-in-cell method and Monte Carlo simulation, the resonance absorption mechanism is investigated. Simulation results demonstrate the existence of surface wave resonance and show the high efficiency of heating electrons. The positions of resonant points, the resonance width and the spatio-temporal evolution of the resonant electric field are presented, which accord well with the theoretical results. The paper also discusses the effect of pressure on the resonance electric field and the plasma density.

Surface plasmon resonance sensor based on molecularly imprinted films for the detection of pentaerythritol tetranitrate （PETN）

A novel surface plasmon resonance （SPR） sensor based on molecularly imprinted films （MIFs） was developed for the detection of pentaerythritol tetranitrate （PETN）. In this work, the thin MIFs were formed on a gold sensor chip through thermal co-polymerization of functional mono- mers （methacrylic acid, MAA） and crosslinking monomers （ethylene glycol dimethacrylate, EGD- MA） in the presence of template molecules PETN. The template molecules PETN were subsequently removed from the MIFs simply by rinsing the MIFs with a mixture of acetonitrile and acetic acid 9：1 （ v/v）, thus the recognition sites were formed for specific detection of PETN. According to the mass coverage equation, the surface coverage of removed PETN from MIFs was about 10. 8 ng/mm~. The developed SPR sensor allowed for the detection of PETN at concentration down to 10-~~ mol/L. A control experiment utilizing an analogue cyclotrimethylenetrinitramine （RDX） showed MIFs＇ good selectivity to PETN.

Improvement of the Specificity of Surface Plasmon Resonance with BSA-modified Chip

A chip was modified with bovine serum albumin （BSA）, then interaction between glutathione （GSH） immobilized on the top of BSA and glutathione-S-transferase （GST） was examined, using surface plasmon resonance （SPR）. The SPR results showed that BSA-modified chip was effective not only in binding the target proteins but also in suppressing the nonspecific binding （NSB） of proteins.

Development and Application of Time-Resolved Surface Plasmon Resonance Spectrometer

Surface plasmon resonance (SPR) sensor, an optical sensor exploiting special electromagnetic waves-surface plasmon polaritons to probe interactions between an analyte in solution and a molecular recognition element immobilized on the SPR sensor surface, has been widely used in various realms, such as investigating biomolecular interactions and binding properties, detection of biological and chemical analytes, environmental monitoring, food safety and medical diagnostics. This paper reviews the development of SPR sensors and SPR commercial instruments, and emphatically introduces the time-resolved surface plasmon resonance (TR-SPR) techniques. The excellent performances of high sensitivity and rapid detection are easily achieved with TR-SPR spectrometer, whereas the traditional SPR spectrometer cannot be accomplished. Therefore, TR-SPR spectrometer is appropriate for real time analysis of bio-recognition events and small molecular dynamics. However, only two commercial TR-SPR instruments have been exhibited at present, Thermo FT-SPR 100 and Autolab ESPRIT (SPRINGLE). Unfortunately, the high-priced instruments are not suitable for extensive applications in laboratories at present. Herein, a novel commercial TR-SPR spectrometer has been introduced in this review.

纳米金用于SPR传感器检测小分子的研究进展

近年来,表面等离子体共振(Surface Plasmon Resonance,SPR)技术因具有可实时、动态监测SPR芯片上分子间相互作用的优点,而广泛应用于小分子传感检测领域。信号放大是小分子SPR传感器的重要研究内容,它决定小分子能否被检出及传感器灵敏度,因此信号放大技术对其发展非常重要。纳米金因其高电子密度、介电特性及易修饰等特性而用于多种传感器的信号放大。重点介绍近5年来纳米金在小分子SPR传感器方面的应用情况,旨在为小分子SPR传感器的进一步发展提供参考依据。

群智能优化的动态基线调整在光纤SPR传感器信号处理中的应用

将谱宽(β)、基线下测量点数(m)、面积比(λ)作为最佳动态基线的选择依据,在两级适应度函数条件下,利用粒子群优化算法跟踪β、m、λ,寻找最佳组合参数下的动态基线,有效克服了传统基线选择较为随意的问题。搭建了光纤SPR测试装置,采集8种不同浓度的蔗糖标准溶液的光谱数据,将4种质心跟踪法进行实验对比。结果表明群智能优化动态基线法的预测精度和相关性均最好,可以有效提取质心参数,消除光源波动对测试结果的影响,为实现光纤SPR实时在线监测提供了一种有效途径,其共振波长拟合度为0.996 3,RMSE为1.78。另外,考察了三种质心计算参数的主导地位,结果表明:在设定相同适应度情况下,固定m方法效果最好,进而为质心参数的选择控制提供有效依据。

波长型SPR检测仪的灵敏度探讨

利用自行设计构建的可变入射角的波长型表面等离子体共振(SPR)检测仪,在不同浓度的蔗糖溶液中测定了不同入射角度(80°～66°)的共振曲线,经过处理得到共振峰位、半高宽及灵敏度随入射角和样品折射率变化的三维图像.在此基础上探讨了波长型SPR检测仪的主要参数对仪器性能的影响,从理论和实验上证明了影响灵敏度的主要因素为共振波长,并且随着共振波长的增大,检测灵敏度迅速提高.

SPR生物传感器及其应用进展

基于表面等离子体共振 (SPR)技术的光学生物传感器是进行生物分子相互作用分析的一种先进手段。与传统的超速离心、荧光法等相比 ,它具有实时检测、无需标记、耗样最少等特点 ,在药物筛选、临床诊断、食物及环境监控和膜生物学等领域中的新兴应用日益扩大 ,并且已成为生命科学和制药研究的一种标准的生物物理学工具。综述了近几年国际上生物传感器的应用进展情况 。

SPR传感器的应用及其发展

表面等离子共振(SPR)传感器是一项新兴的生物化学检测技术,具有灵敏度高、检测方便快捷、可实现在线检测等许多优点,可广泛应用于材料科学、环境保护、食品工业等直接关系人类生存发展的诸多领域。首先介绍了SPR传感器的发展历史及其工作原理,然后综述了SPR传感器的结构和分类,具体包括棱镜耦合式SPR传感器、集成光波导耦合式SPR传感器、光纤SPR传感器和光栅耦合式SPR传感器的结构,着重描述了SPR传感器的最新发展趋势,重点介绍了分布式SPR传感器、光纤SERS传感器的发展状况。

SPR生物传感器检测牛奶中氨苄青霉素残留

将表面等离子体共振(SPR)传感器的高灵敏性与抗原抗体的高亲和性相结合,通过自组装分子技术将抗生素的单克隆抗体固定到传感器金膜表面,用于特异性吸附牛奶中的抗生素,实现了抗生素残留的快速、痕量检测。由于牛奶的成分复杂,在测量过程中牛奶中的某些成分产生的非特异性固定引入了极大的测量误差。因此,对牛奶进行了脱脂和稀释预处理,通过实验比对发现,对牛奶进行脱脂并稀释4倍后,其产生的非特异性固定基本消除,接近了纯水的测量水平。最后,对预处理后的牛奶进行了多浓度测量,并建立了不同浓度的氨苄青霉素牛奶样品的工作曲线。所采用传感器的最低测量限(LOD)达到了1.56μg/L(变异系数为7.8%),低于欧盟规定的牛奶中氨苄青霉素的最低检出限。

SPR免疫竞争法研究小分子吗啡与其抗体间作用的动力学特征

表面等离子体共振技术 ( SPR)主要应用于生物大分子相互作用的研究 ,本文采用溶液竞争法 ,测定了小分子吗啡与其抗体作用的结合常数 K1,并计算了吗啡抗体与吗啡化牛血清白蛋白的结合常数 K2 .证明了多抗对抗原的亲和力较单抗大 ,并表明大分子蛋白质的存在对抗体与待测物的结合有阻碍作用 .

一种高精度SPR生物传感器的设计与实现

表面等离体共振(SPR)技术被广泛应用于表面检测、生化免疫分析、药物筛选和环境监测等领域。介绍一种自行设计的基于Kretschmann结构的角度检测型SPR生物传感器。该装置采用角度连续扫描的方式,利用2个独立的步进电机分别驱动固定有棱镜和光电检测器件的大小转盘,可以进行单一样本的高精度分析。测试结果表明:该传感器具有很高的重复性与稳定性,噪声小、精度高。

纳米金标记抗体增强SPR检测大肠杆菌O157∶H7

将金纳米粒子(AuNPs)标记的大肠杆菌O157∶H7(E.coli O157∶H7)的多克隆抗体(PAb)作为二抗,采用氨基偶联法将PAb固定在传感器表面作为一抗,通过三明治方法用双通道表面等离子体子共振(SPR)传感器对E.coli O157∶H7进行检测,并与SPR直接法检测进行了比较.结果表明,直接法的检出限为103cfu/mL,线性范围为103～109cfu/mL;AuNPs增强三明治法的检出限为10 cfu/mL,线性范围为10～1010cfu/mL,灵敏度比直接法提高了100倍,且具有更宽的检测范围.本方法不仅检测时间短,而且具有良好的选择性和重现性.