用表面等离子体子共振传感器测定人心肌肌钙蛋白I的研究

采用自组装表面等离子体子共振(SPR)传感装置,固定入射角,以波长为变量,以CCD为检测系统,用对金和抗体均有较强吸附作用的葡萄球菌A蛋白作为基底膜,观测了人心肌肌钙蛋白I的抗体和抗原之间免疫反应的动力学过程,并进行了人心肌肌钙蛋白I的定量测定.结果表明,人心肌肌钙蛋白I的浓度在5.0～50μg/L范围内与传感器的响应值呈线性关系.     

表面等离子体激元共振光化学传感器的研究

自行设计并组装了一套全波长表面等离子体激元共振光化学传感器实验装置;研究了以银膜为基底的传感器的稳定性、可逆性及干扰情况;在575nm波长处,测定乙醇的灵敏度为4.6×10^-4折射率单位,RSD≤1.4%,定量测定范围为0.5%～70%.分析了一些实际样品,结果与标准方法的测定值相吻合.     

波长检测型表面等离子体共振传感器对硫堇电聚合成膜的原位分析

利用波长检测型表面等离子体共振(SPR)传感器对硫堇在金膜表面的电化学聚合成膜过程进行了跟踪分析.结果表明,在固定入射角下SPR共振波长随循环伏安扫描周数的增加而线性红移,表明聚硫堇膜的生长是匀速的;扫描100周后共振波长红移总量为96.6 nm.对该实验结果进行理论拟合,得出聚硫堇膜的厚度约为71 nm.聚硫堇膜在酸性缓冲液中的电化学活性很高,其电化学反应过程受扩散控制,在一个完整的循环伏安扫描过程中SPR共振波长的变化完全可逆,说明聚硫堇膜的氧化反应和还原反应是一对可逆过程.与还原态聚硫堇膜相比,氧化态聚硫堇膜对应的SPR共振波长较大,说明氧化态聚硫堇膜折射率高.     

An optical surface plasmon resonance biosensor for determination of tetanus toxin

Surface plasmon resonance (SPR) has been successfully applied for the simple, rapid, and label-free assay of various biomolecules. This assay evaluates a novel wavelength modulation SPR biosensor for the detection of tetanus toxin. The wavelength modulation SPR biosensor is designed based on fixing the incident angle of light and measuring the reflected intensities in the resonance wavelength range spanning 400-800 nm simultaneously. Tetanus toxin (TeNT), one of the most potent toxins known, is synthesized as a 150 kDa single polypeptide chain. The SPR biosensor has been shown to be capable of directly detecting concentration of tetanus toxin as low as 0.028 Lf ml⁻¹. Under selected experimental conditions, the SPR biosensor has a good reproducibility, sensitivity and reversibility. The results illustrate how wavelength modulation SPR biosensor can be used to detect biomolecular interactions.     

基于表面等离子体子共振的B因子传感器

以分辨率较高的一米光栅单色仪为分光系统,光电倍增管为检测系统,改进了自行组装的表面等离子体子共振(SPR)传感装置,提高了仪器的检测能力约50倍,对于发展改变波长模式的SPR传感器具有重要意义。以对金和抗体均有较强吸附作用的葡萄球菌A蛋白为基底膜,观测了人的B因子抗体和抗原之间免疫反应的动力学过程,并研究了B因子的定量测定。结果表明,B因子抗原的浓度在0.02～5μg/mL范围内与信号的响应值呈线性关系。该传感器灵敏度高,选择性和重现性均好。     

基于表面等离子体子共振的白蛋白免疫传感器的研究

采用自行组装的全波长表面等离子体子共振(SPR)传感装置,以对金和蛋白抗体均有较强吸附作用的A蛋白作为基底膜,测试了A蛋白在金膜表面结合的动力学常数,其结果为2.3×10⁵L/(mol·s).研究了在A蛋白基底膜上白蛋白抗体的定向自组装程度和速率.观测了白蛋白抗体与抗原之间免疫反应的动力学过程,并优化了实验条件.结果表明,白蛋白抗原的浓度在0.02～10mg/mL范围内与信号的响应值呈良好的线性关系.将此SPR传感器用于糖尿病肾病患者尿蛋白的检测,结果较好.     

High-resolution surface plasmon resonance sensors based on a dove prism

Wavelength interrogation surface plasmon resonance (SPR) spectroscopy using a dove prism combines a simple and inexpensive optical design with high-resolution refractive index monitoring and biosensing. A BK7 dove prism inverts an optical image with a total internal reflection angle of 72.8°, an angle active in SPR. Hence, a unique system can accomplish SPR biosensing using wavelength interrogation and also perform SPR imaging. This optical configuration advantageously uses a single axis optical path between each optical component, simplifying the optical design of SPR instruments without compromise of the analytical performance. Fluidics were also incorporated to the instrument design for efficient sample delivery. The SPR instrument is characterized in terms of refractive index (RI) sensitivity, RI resolution, reproducibility, and application for monitoring low concentration biological events. Data analysis methodologies are compared for improved resolution of the measured response. Raw data analyzed using a minimum hunting procedure results in RI resolution in the 10⁻⁶ range, while pre-treating data with singular value decomposition improves the resolution by one order of magnitude. Depending on the spectrophotometer employed, the RI range accessible can be easily tuned; examples with a 550-850 nm and a 550-1100 nm spectrophotometers are shown and results respectively in RI ranges of 1.32-1.39 RIU and 1.32-1.42 RIU. Monitoring of μM concentration of β-lactamase is performed using the wavelength interrogation configuration of the biosensor. Finally, a SPR image of a surface with a water droplet (volume = 500 nL) was obtained using the dove prism SPR with a band pass filter and a CCD camera. SPR using a dove prism configuration combines advantages of portable SPR instruments, SPR imagers and research-grade SPR instruments in a unique platform.     

Immunosensor Based on Surface Plasmon Resonance for Antigen Recognition

A novel immunosensor based on surface plasmon resonance（SPR） has been developed for the recognition of antigen. The sensor was designed on the basis of the fixed angle of incidence and measuring the reflected intensities in a wavelength range of 430--750 nm in real-time. An ultra-bright white light-emitting diode（LED） was used as the light source. Molecular self-assembling in solution was used to form the sensing membrane on gold substrate. It has been seen that the sensitivity of the SPR sensor with 3-mercaptopropionic acid（MPA）/protein A（SPA） sensing membrane is considerably higher than that with MPA or SPA modified sensing membrane. The kinetic processes on the sensing membrane were studied. The human B factor（Bf）, an activator of complement 3（C3）, was recognized among the other antigens. This sensor can also be used for other antigen/antibody or adaptor/receptor recognition. Under optimized experimental conditions, the sensor has good selectivity, repeatability, and reversibility.     

New Optical Chemical Sensors Based on Surface Piasmon Resonance

A kind of new optical chemical sensors based on surface plasmon resonance (SPR) have been developed recently in this laboratory. Traditionally, the sensors based on SPR are making use of a coupling prism coated with a thin gold film and performed by varying the incidence angle with a goniometer.     

An optical immunosensor based on surface plasmon resonance for determination of bFGF

An optical immunosensor based on surface plasmon resonance (SPR) has been developed for immunosensing. The sensor is designed on the basis of fixing incident angle of light and measuring the reflected intensities in the wavelength range of 400-800 nm simultaneously. The SPR spectrum was shown in terms of reflected light intensities versus wavelengths of incident light. The intensity of the reflected light reaches the minimum at the resonant wavelength. Molecular self-assembling in solution is used to form the sensing membrane on gold substrate. The kinetic processes of sensing monolayer formation were studied. The basic fibroblast growth factor, a kind of basic polypeptide, was determined in the concentration range of 0.24-9.6 μg/ml. Under optimum experimental conditions, the sensor has a good repeatability, reversibility and selectivity.     

Fiber-optic surface plasmon resonance for vapor phase analyses

Fiber-optic sensors based on surface plasmon resonance (SPR) for direct refractive index (RI) measurements of samples with the RI between 1.00 and 1.30 are described. Most applications of SPR sensors are designed to function near the refractive index of water (1.3330 RI). The RI changes of aqueous solution (RI, ca. 1.34) can easily be monitored by silica-fiber (RI, 1.4601 at 550 nm) based SPR sensor. With regard to gas species detection, the fiber-optic SPR sensor must be modified for sensitivity to changes in refractive index near 1.0008 (i.e., RI of air). However, the silica waveguide has a prohibitively high RI for unmodified monitoring of the RI changes of gas. The silica-fiber based SPR probe design presented here is based upon the modification of the probe geometry to the ability to tune the SPR coupling wavelength/angle pair. In this study, the tapered silica-based fiber SPR sensors are shown to directly determine the RI changes of gas species and the density change of dry air.     

Surface plasmon resonance as a time-resolved probe of structural changes in molecular films: considerations for correlating resonance shifts with adsorbate layer parameters

Surface plasmon resonance (SPR) spectroscopy is an efficient probe of transient structural changes in molecular films. To analyze kinetic SPR data for such systems, generally it is necessary to adapt an adequate theoretical framework that would allow one to express the measured optical quantities (time-dependent shifts of the resonance angle or wavelength) in terms of the structural parameters (layer thickness, mass density, or surface coverage) of the sample molecules. We present here theoretical calculations and illustrative experimental results to address certain essential elements of this type of data analysis for transient SPR systems. The phenomenological framework we consider here is based on multilayer reflectivity calculations, and can be applied to a broad class of systems involving ordered molecular layers on supporting gold films. A typical application of these calculations is demonstrated through the analysis of specific SPR experiments designed to probe the kinetics of pH-induced structural changes in a molecular film of 11-mercaptoundecanoic acid (MUA) on a thin gold film.     

Far‐ and Deep‐Ultraviolet Surface Plasmon Resonance Sensor

Plasmonics in the UV region has been widely focused because of the higher energy and the abundant electronic resonances compared to the conventional visible plasmonics. Recently, we have investigated the surface plasmon resonance (SPR) properties of the Al film, aiming for the application as refractive index sensors. Utilizing the UV lights, we expect three advantages: high sensitivity, material selectivity, and surface selectivity. By using an original attenuated total reflectance spectroscopic instrument, Al‐SPR angle and wavelength were investigated with changing environments on the Al film. Al film thickness and materials of prisms on which Al was evaporated were also important factors for the SPR properties. By optimizing the conditions, the Al film worked as a sensor both in air and in liquids. In addition, our established system expands the plasmonics into an even higher energy region than 200 nm, while the UV‐plasmonics have been studied in the wavelength region longer than 200 nm.     

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.     

Single-crystal sapphire-fiber optic sensors based on surface plasmon resonance spectroscopy for in situ monitoring

Single-crystal sapphire-fiber optic sensors based on surface plasmon resonance (SPR) for refractive index (RI) measurements of aqueous and hydrothermal water solutions are described. Accurate measurement of RIs is essential to efficient operation and control of broad range of engineering processes. Some of these processes are carried out with harsh environments, such as high-temperature, high pressure, and chemical corrosion. These extreme physical conditions are proving a limiting factor in application of the conventional silica-based optical sensors. Single-crystal sapphire is an ideal material for sensor applications, where reliable performance is required in the extreme environment conditions. With regard to the liquid species detection, most applications of SPR sensors are designed to function near the refractive index of water (1.3330 RI). The RI changes of aqueous solution can be easily monitored by silica-fiber (RI, 1.4601 at 550 nm) based SPR sensor. However, the sapphire waveguide has a prohibitively high RI (1.7708 at 546 nm) for unmodified monitoring of the RI changes of aqueous solutions. For that purpose, a practical SPR probe geometry has been applied to the ability to tune the SPR coupling wavelength/angle pair with sapphire-fiber based SPR probe.     

银膜表面等离子体耦合辐射特性的仿真分析

表面等离子体耦合辐射(SPCE)是传统表面等离子体共振(SPR)的逆过程:当分子足够靠近金属薄膜表面时( < 200 nm),其受激辐射的能量可以耦合成SPR模式并定向辐射到棱镜中.由于具有场增强特性、高收集效率和优异的表面选择性, SPCE作为一种新的表面分析技术已经在荧光和拉曼光谱领域得到了有效的应用.本文采用光学互易定理简化传统SPCE的计算方法.通过计算,我们得到了SPCE一维和二维辐射功率密度分布,表面选择性,辐射角的波长色散特性,辐射角半峰宽与银膜厚度的关系.仿真结果与已报到的实验结果吻合良好,验证了该方法的有效性.     

波长检测型表面等离子体子共振生物传感器测定β-环糊精与血清白蛋白的相互作用

采用自行组装的表面等离子体子共振(SPR)传感装置, 固定入射角, 以波长为变量, 以电荷耦合器件(CCD)为检测系统, 用对金和蛋白质均有较强作用的巯基丙酸作为基底膜, 分别监测了β-环糊精(CD)与人血清白蛋白(HSA)、牛血清白蛋白(BSA)反应的动力学过程, 并分别计算了它们的动力学常数、热力学常数及键合百分率. 此外, 对传感器的再生性也进行了研究. 结果表明, β-CD与HSA, BSA相互作用的平衡常数分别是7.79和51.00 μmol/L, 且键合百分率都很高, 分别是98.77%和94.25%. 这些结果有力地说明了β-CD作为药物载体, 可以提高生物利用度, 延长药物半衰期.     

小型波长检测型表面等离子体共振分析仪的设计与研制

小型波长检测型表面等离子体共振(SPR)分析仪采用固定光的入射角,监测共振波长变化的测量模式,可进行多波长同时测量.设计并组装了SPR分析仪中的微型光纤光谱仪,采用光导纤维输入被测光,固定全息衍射光栅分光,线阵CCD光电传感器检测,可检测的波长范围是500～900 nm,分辨率0.23 nm.自行编制了控制传感器数据采...     

Surface plasmon resonance study on enhanced refractive index change of an Ag ion-sensing membrane containing dithiosquarylium dye

In this study, we have fabricated an Ag⁺ ion-sensing membrane with a dithiosquarylium (DTSQ) dye containing a polymeric film. The selective sensing signal through the electrostatic interaction between the DTSQ dye and the Ag⁺ metal cation was effectively transduced to the refractive index (RI) change corresponding to shifts of the surface plasmon resonance (SPR) angle. In addition, a good selective Ag⁺ ion detection appeared in a wide concentration range from 10⁻⁴ to 10⁻¹² M. The resonance angle shift is interpreted with Fresnel equations and Kramers-Kronig relation. In light of these calculations, the enhanced RI increase in this sensing membrane appeared to be caused by the decrease of absorption coefficient of DTSQ dye around the wavelength of SPR probe beam. These results suggest that chromogenic approaches (λ_max control of Ag⁺ ion-sensing membrane with a DTSQ dye by appropriate molecular design) related to SPR phenomena (RI change at the wavelength of probe beam) offer a good strategy for highly sensitive metal ion detection.     

表面等离子体共振生物传感器研究人参皂甙与血清白蛋白的相互作用

To use a newly developed wavelength modulation surface plasmon resonance （SPR） biosensor, an experimental protocol was developed to investigate the interaction of ginsenosides with serum albumin. With a known concentration of the ginsenosides, bound percentages of the ginsenosides with human serum albumin （HSA） or bovine serum albumin （BSA） were obtained. SPR technique could require no labeling and this method provided the detailed information on association and disassociation of molecules in real time. The results indicate that the sensitivity of wavelength modulation SPR biosensor is sufficient for detection and characterization of binding events involving low-molecular weight compounds and their immobilized protein targets.