LiNbO3棱镜耦合双金属薄膜表面等离子共振传感器

高折射率铌酸锂(LiNbO3)(2.202)为棱镜耦合激发的角度调制型表面等离子共振传感器,利用反射率公式优化单层银膜、金膜和双层银/金膜传感器薄膜的厚度,分别计算了优化厚度的传感器在检测样品折射率为1.330时的共振角、灵敏度、峰值半宽度(FWHM)和品质因数(FOM),理论计算表明:双层金属薄膜,随着金膜厚度的增加,传感器灵敏度增加,但峰值半宽度增加,品质因数下降.综合考虑,选择银/金(41/5)优化组合,传感器品质因数为优化的单层金膜(47 nm)传感器品质因数的2倍以上,另外,与常用的BK7玻璃棱镜耦合相比,LiNbO3棱镜耦合具有较大的样品动态检测范围.优化厚度的传感器实验检测糖水浓度表明:糖水浓度与共振角为线性比例关系.     

动态范围可调的波导型SPR传感器模型

表面等离子体共振 (SPR)技术是一种简单直接的传感技术 ,SPR对金属表面附近的折射率的变化极为敏感 ,利用这一性质 ,表面等离子体共振传感器已成为生物传感器研究领域的热点。现提出一种电光调制波导型SPR模型 ,模拟计算表明该模型在不损害灵敏度的条件下 ,扩大了探测的动态范围。     

Surface plasmon resonance in chalcogenide glass-based optical system

The surface plasmon resonance phenomenon has been studied in a chalcogenide glass-based optical system. IR transmission properties of these materials combined to their high refractive indices lead to advantageous properties for sensing. In this study, numerical simulations have been carried out to investigate the potentialities of sulfide glass from the GeGaSbS system as a coupling prism material. Then, an angular modulation SPR biosensor has been set up in the Kretschmann–Raether arrangement. Experimental data are consistent with numerical calculation and the detection limit of the sensor is 3 × 10⁻⁵ RIU. These preliminary results are promising. Further investigations have to be carried out to confirm the great potentialities of those materials for SPR-based biosensor.     

基于Matlab的定角度SPR传感器仿真

从理论上分析表面等离子体共振（SPR）的条件,给出了k层Kretschmann棱镜耦合模型下的反射率R大小的公式,编写了Matlab仿真软件,仿真了4层Kretschmann棱镜耦合模型下的反射率R大小与入射光波长、银膜厚度、棱镜折射率的关系。分析了仿真结果,得出了采用定角度方式时各装置参数的选择依据。     

表面等离子体共振传感检测方法研究

为了找到表面等离子体共振(SPR)检测物体的最佳方法,基于SPR,通过Matlab进行了一系列仿真。对检测物质的可行性进行了讨论,得出SPR能在一定范围内检测物质。对影响SPR现象的因素进行了仿真,得出达到最佳共振效果的参数值。分别对角度调制和波长调制方法进行仿真比较,分析了二者检测不同折射率样品的可行性和特点,选择出了较佳的检测方法。结果得出:达到最佳共振效果的参数值是金膜厚度为45 nm,入射光波长为632.8 nm,棱镜折射率根据实验条件和样品综合选定。角度和波长调制均能较好地检测不同折射率的样品,角度调制检测分辨率低于波长调制。     

Surface plasmon resonance detection of small molecule using split aptamer fragments

It was difficult to detect small molecules directly using conventional surface plasmon resonance (SPR) biosensors since the changes of refractive index, which was resulted by binding small molecules, were usually small. In this paper, split aptamer fragments were used for the construction of SPR biosensor to determine small molecule such as adenosine with high sensitivity. An aptamer for adenosine was designed to be two flexible ssDNA pieces, one was tethered on Au film and the other was modified on Au nanoparticles (AuNPs). In the presence of adenosine, two ssDNA pieces reassembled into the intact aptamer structure and the AuNPs-labeled adenosine-aptamer complex was formed on the Au film. Then, the resonance wavelength shift was enhanced obviously, due to the electronic coupling between the localized plasmon of AuNPs and the surface plasmon wave associated with Au film. The results confirmed that this biosensor could detect adenosine with high sensitivity and selectivity. The limitation of detection (LOD) of this SPR biosensor was ca. 1.5 pM, which was an approximately ca. 2-3 order of magnitude lower than that of those SPR biosensors which utilized competitive methods.     

利用图像SPR分析仪检测多组分蛋白芯片

介绍了一种新型高通量表面等离子体谐振(SPR)生化分析仪。基于图像分析技术和自动进样技术,该仪器可对微阵列SPR敏感芯片进行动态检测,实现高通量、多参数、多组分快速检测和定量分析。对兔IgG和人IgG分别与羊抗兔IgG和羊抗人IgG的免疫结合反应进行了实验检测。结果表明:该分析系统具有灵敏度高、免标记等优点,且阵列芯片中所设置的参比单元可以消除溶液本体折射率和温度变化的影响,提高了测量精度和准确性;另外,芯片可以再生重复使用,降低了测试成本。     

一种小型化SPR生物传感器的设计与实现

介绍了一种采用不规则四边形棱镜设计的小型化表面等离子体共振(SPR)生物传感器。棱镜结构与已有的TI Spreeta传感器类似,但是在尺寸、光学性能等方面做了较大优化。新研制的SPR传感器在光学检测精度和系统集成性等方面也有了很大提高。在光路设计中,采用波长为630 nm的宽光束红光LED作为光源,5 000像素点线阵CCD作为光电检测器,光学检测效果要大大优于TI Spreeta波长为830 nm的近红外光源和128像素点的线阵硅光二极管。在光路优化的同时,系统集成了流动控制模块、信号采集处理模块,形成了一个可实现生物大分子相互作用分析的集成小型化SPR检测装置。利用空气、水及乙醇等进行的SPR实验表明:该装置能够对单一样本进行精确检测,共振角的检测精度高达0.01°,且检测结果线性度高,稳定性好,单一样本的检测偏差小于0.5%。     

基于角度传感器的玻璃材料折射率的测定

在介绍根据布儒斯特定律测量玻璃材料折射率的方法和用磁阻式角度传感器测角原理的基础上,提出一种利用角度传感器测量材料折射率的新方法,实现了角度量和材料折射率的非电量电测。通过用此方法测量2种玻璃样品的折射率与理论值进行比较,发现在不考虑传感器温度漂移及装置的平整性等系统误差的条件下,折射率测量的相对误差小于3%。研究还表明:新型锑化铟磁阻角度传感器的线性范围约200°,为设计非接触式角度量及折射率的自动测量系统打下了基础。     

血液中C反应蛋白的SPR传感检测方法研究

利用表面等离子体共振（SPR）生物传感技术,建立了一种可以快速准确分析血样中C反应蛋白的新方法。SPR传感器采用Kretschmann结构的角度连续扫描方式,使用2个步进电机分别驱动棱镜和光电检测器件转动进行单一样本的高精度分析。将C反应蛋白抗体修饰于敏感芯片表面,通过SPR传感器对血样中C反应蛋白浓度进行检测分析。利用SPR方法和传统免疫比浊法分别检测标准C反应蛋白样本和200份感染性疾病儿童患者（7～10岁,男112名,女88名）的血液样本,结果表明：SPR方法检测标准样本的线性变化区域更大。在患儿血样的检测中,尽管2种方法的结果基本相同,但是SPR检测速度更快,样本需求量更小、重复性更佳。这表明SPR生物传感分析方法在C反应蛋白检测中比传统方法更具优势,有望在临床检验分析中得以广泛应用。     

Sensitivity Comparison of Surface Plasmon Resonance and Plasmon-Waveguide Resonance Biosensors

Plasmon-waveguide resonance (PWR) sensors are particularly useful for the investigation of biomolecular interactions with or within lipid bilayer membranes. Many studies demonstrated their ability to provide unique qualitative information, but the evaluation of their sensitivity as compared to other surface plasmon resonance (SPR) sensors has not been broadly investigated. We report here a comprehensive sensitivity comparison of SPR and PWR biosensors for the p-polarized light component. The sensitivity of five different biosensor designs to changes in refractive index, thickness and mass are determined and discussed. Although numerical simulations show an increase of the electric field intensity by 30-35% and the penetration depth by four times in PWR, the waveguide-based method is 0.5-8-fold less sensitive than conventional SPR in all considered analytical parameters. The experimental results also suggest that the increase in the penetration depth in PWR is made at the expense of the surface sensitivity. The physical and structural reasons for PWR sensor limitations are discussed and a general viewpoint for designing more efficient SPR sensors based on dielectric slab waveguides is provided.     

SPR生物传感器温度特性的理论研究

表面等离子体共振(SPR)生物传感器在生物大分子检测时具有非常高的理论分析精度,但在实际应用过程中传感响应特性容易受到环境温度的影响.在小型化SPR传感器中由于缺乏温度控制模块,这种情况尤为明显.利用理论模型分析研究了环境温度变化对传感系统中光源、棱镜、金属薄膜和待测溶液等不同介质、光学检测器等的物理特性的影响以及由此...     

Searching for optimal sensitivity of single-mode D-type optical fiber sensor in the phase measurement

To improve the sensitivity of a single-mode D-type optical fiber sensor, we selected a D-type optical fiber sensor with 4 mm long and 4 μm core thickness made of a single-mode fiber, a Au-coating on the sensor with a thickness range of 15–32 nm, a light wavelength of 632.8 nm, and an incident angle of 86.5–89.5° for different refractive index (1.33–1.40) sensing. These simulations are based on the surface plasmon resonance (SPR) theory using the phase method which shows that the sensitivity is proportional to the refractive index, Au film thickness and lower incident angle on the sensing interface. The sensitivity is higher than 4000 (degree/RIU), and the resolution is better than 2.5 × 10⁻⁶(RIU) as the minimum phase variation is 0.01°. This device is used to detect the refractive index or gas or liquid concentration in real-time. The proposed sensor is small, simple, inexpensive, and provides an in vivo test.     

Manufacture of robust surface plasmon resonance fiber optic based dip-probes

Surface plasmon resonance (SPR) spectroscopy has been conducted on both prism and fiber optic (FO) based sensors for several years. This technique measures the refractive index (RI) of a solution or layer adsorbed to a thin (50 nm) Au layer on the sensor substrate. To date a succinct set of protocols have not been published regarding the optimization of fiber-based SPR dip-probe sensors. Such sensors would allow application of SPR to a wider variety of applications. This paper focuses on consideration of the choice of fiber, isolation of the mirror from the sensing area, and orientation of the probes in the metal layer sputter deposition chamber in the manufacture of SPR dip-probes for reproducibility and robustness. Optimization of the process yields sensors with a batch to batch reproducibility as low as 0.5 nm in the location of the SPR spectral minima. Further study of RI measurements by the same probe over 2 months show these SPR dip-probes have a long shelf-life. A selection of probes was exposed to various solutions to monitor their drift. The data shows the probes’ response indicated a lowering of the RI measured over a period of 3 or 7 days depending on the probe type. Evidence of surface porosity and damage upon exposure to hydrothermal water seems to indicate these sensors are prone to chemical attack. Further research is needed to characterize this attack and allow creation of more robust sensors.     

SPR生物传感器的应用现状与发展趋势

表面等离子体共振(SPR)生物传感器是一种基于物理光学原理的新型生化分析系统.与传统的超速离心、荧光法相比,具有实时检测、无需标记、耗样量少等特点.介绍了SPR生物传感器的基本原理,着重介绍了SPR生物传感器在生命科学,药物残留,疾病诊断以及食品检测中的应用,并对其发展趋势进行了展望.     

Influence of ions on the surface plasmon resonance spectrum of a fiber optic refractive index sensor

Surface plasmon resonance (SPR) spectra of a fiber optic SPR probe coated with thin gold layer have been studied experimentally for four ionic (NaCl, KCl, Na₂SO₄ and MgCl₂) and two non-ionic (sucrose and urea) liquid samples of different refractive indices. For the same value of refractive index, the response curves for ionic and non-ionic liquid samples have been found to differ, implying the influence of ions on the resonance wavelength of the SPR spectrum. It is observed that the resonance wavelength, for a given refractive index of the liquid, is higher for ionic sample than that in the case of non-ionic one. This extra increase in resonance wavelength is attributed to the interaction of ions with the free electrons of the metal film. The study finds importance in situations where ions get generated during the processes. In such studies, the effect of ions on SPR spectrum must be incorporated otherwise the SPR spectrum may get wrongly interpreted.     

Dynamically modulated intensity interrogation scheme using waveguide coupled surface plasmon resonance sensors

An electro-optically modulated intensity interrogation method based on tunable waveguide coupled surface plasmon resonance sensors has been proposed. It has been theoretically and experimentally demonstrated that the proposed scheme can enable sensitive measurement of measurand variations. By modulating the refractive index in the waveguide layer, this interrogation method yields modulated signal whose amplitude is related to measurand's refractive index. This amplitude modulated signal offers a higher signal to noise ratio and eliminates additive noise in the sensor system. A preliminary investigation using saline buffers with different NaCl concentrations shows a resolution of 2.3 × 10^?6 refractive index unit by our approach. Resolution can be controlled by the amplitude of the applied modulation voltage and can be further enhanced by optimizing the device structure or improving the electro-optical (E-O) coefficient of the E-O material. This approach is simple, stable, and promising for low-cost or multi-channel SPR biosensor applications.     

光纤表面等离子体波传感器测量液体折射率的研究

针对表面等离子体波共振现象产生的原理和激发条件进行了阐述.通过自行设计的一套光纤表面离子体波传感器测试系统,测定了从0%～70%的不同浓度甘油水溶液折射率与共振波长的关系,实验结果具有较好的重复性并和理论分析相吻合.由此得到一种基于光纤SPR传感技术的液体折射率测量方法.     

Resonance wavelength-dependent signal of absorptive particles in surface plasmon resonance-based detection

We describe the resonance wavelength-dependent signal of absorptive particles in surface plasmon resonance (SPR)-based detection using both modeling and experimental results. The particles, gold nanocages, have a significant absorption cross-section in the nearinfrared (NIR), resulting in a wavelength-dependent refractive index as measured by SPR. The SPR signal due to the nanocages varies by 4-fold over resonance wavelengths from 650 nm to 950 nm. The greatest SPR signal occurs at the longest resonance wavelengths; its magnitude is due to the inherent increase in sensitivity of SPR on gold with increasing wavelength and the optical absorption properties of the nanocages.     

Fast surface plasmon resonance imaging sensor using Radon transform

Surface plasmon resonance (SPR) imaging technique is proposed in which a diverging laser beam at given frequency was used to illuminate the entire sensor surface in Kretschmann-Raether configuration. A pattern of dark intensity line on bright background is observed corresponding to the SPR dip at an angular range depending on the refractive index of the adjacent analyte and monitored by a two-dimensional CCD detector. A novel Radon transform based detection algorithm for the SPR line pattern is proposed, which is non sensitive to the laser speckle noise and improves the accuracy.