基于金银合金薄膜的波长检测型表面等离子体共振传感器

从实验和理论两方面详细研究了金银合金膜表面等离子体共振(SPR)传感器在可见光波段的敏感特性.实验方面,通过在玻璃基底上溅射50 nm厚的金银合金薄膜制备了一种新型的SPR传感芯片,并且自行搭建了基于Kretschmann结构的波长检测型SPR传感器测试平台.利用不同浓度的氯化钠(NaCl)水溶液和浓度为10μmol·L-1的牛血清蛋白(BSA)水溶液分别作为折射率样品和分子吸附样品,研究了传感器的折射率灵敏度和吸附灵敏度,并与金膜和银膜SPR传感器进行了对比研究.结果表明,对于折射率灵敏度的测试,金银合金膜SPR传感器大幅高于金膜SPR传感器,略低于银膜SPR传感器;而对于吸附敏感的研究,金银合金膜SPR传感器的灵敏度与银膜SPR传感器相近,是金膜SPR传感器的3倍.理论方面,利用菲涅尔公式和等效折射率计算公式仿真计算了这三种薄膜结构的SPR传感器的灵敏度和精确度,结果指出金银合金膜SPR传感器的灵敏度与银膜SPR传感器接近,是常规金膜SPR传感器的2.31倍,而半高峰宽仅为金膜和银膜SPR传感器的1.36倍.在稳定性方面,金银合金膜SPR传感器与金膜SPR传感器均具有良好的化学稳定性,而银膜SPR传感器较易氧化,使用寿命低,不常被采用.综上,金银合金膜在改善传感器灵敏度的同时,不会降低精度,是一种高灵敏、低成本、良好稳定性的SPR传感器敏感材料.     

基于金银合金薄膜的波长检测型表面等离子体共振传感器

从实验和理论两方面详细研究了金银合金膜表面等离子体共振（SPR）传感器在可见光波段的敏感特性. 实验方面,通过在玻璃基底上溅射50 nm厚的金银合金薄膜制备了一种新型的SPR传感芯片,并且自行搭建了基于Kretschmann 结构的波长检测型SPR传感器测试平台. 利用不同浓度的氯化钠（NaCl）水溶液和浓度为10 μmol·L^-1的牛血清蛋白（BSA）水溶液分别作为折射率样品和分子吸附样品,研究了传感器的折射率灵敏度和吸附灵敏度,并与金膜和银膜SPR传感器进行了对比研究. 结果表明,对于折射率灵敏度的测试,金银合金膜SPR传感器大幅高于金膜SPR传感器,略低于银膜SPR传感器;而对于吸附敏感的研究,金银合金膜SPR传感器的灵敏度与银膜SPR传感器相近,是金膜SPR传感器的3倍. 理论方面,利用菲涅尔公式和等效折射率计算公式仿真计算了这三种薄膜结构的SPR传感器的灵敏度和精确度,结果指出金银合金膜SPR传感器的灵敏度与银膜SPR传感器接近,是常规金膜SPR传感器的2.31倍,而半高峰宽仅为金膜和银膜SPR传感器的1.36 倍. 在稳定性方面,金银合金膜SPR传感器与金膜SPR传感器均具有良好的化学稳定性,而银膜SPR传感器较易氧化,使用寿命低,不常被采用. 综上,金银合金膜在改善传感器灵敏度的同时,不会降低精度,是一种高灵敏、低成本、良好稳定性的SPR传感器敏感材料.     

Characteristics of a surface plasmon resonance sensor combined with a poly(vinyl chloride) film-based ionophore technique for metal ion analyses.

The characteristics of a surface plasmon resonance (SPR) sensor prepared by coating a metal film evaporated on a prism with a polymer film containing tetra-n-butyl thiuram disulfide (TBTDS) were studied. The differences in the sensitivity, selectivity, and detection limit for a Zn2+ ion of the SPR sensor were reported as a function of the thickness of the polymer film, the kind of a metal film, and the kind of a polymer film. The thinner was the polymer film, the higher was the sensitivity, and the lower was the detection limit. The Ag film gave to the SPR sensor higher sensitivity than the Au film. TBTDS contained in the poly(vinyl chloride) (PVC) film slightly improved the selectivity toward the Zn2+ ion. A non-conditioned poly(methyl methacrylate) (PMMA) film containing TBTDS gave a lower detection limit of 1.0 x 10(-6) mol/l, which is similar to that obtained by using an ion selective electrode (ISE) method, than the PVC film. The PVC film, however, gave higher concentration resolution than the PMMA film.     

基于色相算法的表面等离子体共振成像传感器对苯并芘的敏感特性

报道了一种用于原位探测水中苯并芘的彩色表面等离子体共振成像(SPRI)传感器,该传感器既能提供直观的图像信息,又能借助色相算法定量分析待测物质的浓度及其吸附/脱附过程。首先利用自制的波长-图像同步检测型SPR传感器测试了裸金薄膜芯片在不同入射角下的共振波长和共振图像,然后利用色相算法建立了SPR共振波长与图像色相的依赖关系,基于该依赖关系获得了SPR传感器最佳色相灵敏度对应的起始共振波长约为650 nm;另一方面,制备了聚四氟乙烯涂覆的SPR传感芯片,基于聚四氟乙烯膜对水中苯并芘的可逆富集作用实现了苯并芘的原位快速探测。实验取得以下4个结果:(1)在20-100 nmol?L-1浓度范围内彩色SPR图像的平均色相值随着苯并芘浓度的升高线性减小;(2)对100 nmol?L-1的苯并芘的响应和恢复时间分别约为7和5 s;(3)由于聚四氟乙烯膜的厚度大于SPR消逝场穿透深度,检测结果不受溶液折射率影响;(4)在聚四氟乙烯敏感膜厚度较小且不均匀的情况下,传感器容许获取敏感膜的不同厚度区域对苯并芘的色相灵敏度。实验结果有力地证明了这种彩色SPR图像传感器在生化物质检测中具有良好的应用前景。     

Simplification and evaluation of a gold-deposited SPR optical fiber sensor.

The structure of the sensing element of a gold-deposited optical fiber sensor was simplified and quantitative analyses of various alcohols with the sensor showed improvement of the performance. The sensor uses surface plasmon resonance (SPR) at the interface of a sample solution and a thin (10 - 70 nm) gold film deposited on half of the exposed core of the optical fiber. The sensor with a film thickness of 45 nm can detect a small change of 5.6 x 10(-5) refractive index (RI) units in the refractivity. The response time is less than 0.5 min and the relative standard deviation for measurements is less than or equal to 1%. A straight line with a correlation coefficient of 0.9995 was obtained below 10%, v/v in the calibration curve for methanol solutions of benzyl alcohol. The minimum of the response curve due to the maximum excitation of SPR in the refractivity range from 1.33 to 1.44 RI units shifts to a lower refractivity as the film becomes thicker. The response curves of the sensors were calculated from SPR theoretical equations while considering of the distribution in the thickness of the deposited gold films. The improvement in the performance of the sensor is discussed.     

Refractive Index Measurement in Sucrose Solution and Beverage Using Surface Plasmon Resonance Sensor Based on Hetero-core Structured Fiber Optic

The surface plasmon resonance (SPR) sensor was fabricated by depositing silver thin film on the surface of hetero-core structured fiber optic. The SPR sensor based on hetero-core structured fiber optic was applied to measure refractive index of sucrose solution and fruit juices. The sensor part was immersed in sucrose solution and/or juice and the propagating light spectra were measured. It was shown that the fiber optic SPR sensor showed a good agreement with that measured by conventional refractometer.     

A novel polymerization of ultrathin sensitive imprinted film on surface plasmon resonance sensor

A new surface-initiated polymerization based on pasting the initiator on a sensor chip surface was applied to prepare a malachite green (MG) imprinted ultrathin film on a surface plasmon resonance (SPR) sensor. First, the initiator (2,2-azoisobutyronitrile) was pasted on the gold surface using polyvinyl chloride (PVC). The initiator-covered gold chip was then soaked in a pre-polymerization solution prepared by dissolving methacrylic acid (functional monomer), ethylene glycol dimethacrylate (cross-linker), and MG (template) in DMSO in a weighing bottle. Finally, the weighing bottle was placed in a vacuum oven and thermal-initiated polymerization was conducted at 60 °C for 16 h. This method was simple and time-saving compared with the commonly used surface-initiated polymerization. More importantly, the molecularly imprinted polymer (MIP) film prepared using this method was much thicker than that of commonly used methods; the adsorption quantity was also much larger. The MIP modified SPR sensor showed high sensitivity and selectivity as well as good stability in detecting MG. The results suggest that the ultrathin MIP film prepared using the new method in this study is suitable to serve as the recognition element of the SPR sensor.     

Theoretical analysis of gold-deposited optical fiber sensor and characterization of the gold film.

Gold-deposited optical fiber sensors with film thicknesses from 30 to 60 nm were prepared, and the responses to a wide range of a refractivity (1.33-1.54 refractive index (RI) units) were investigated both experimentally and theoretically. The response curve of the sensor has two minima in the refractivity range from 1.33 to 1.44 and at 1.462 RI units. The former minimum is due to surface plasmon resonance (SPR) in the thin gold film, and shifts to a lower refractivity as the film becomes thicker. The response curves of the sensors with film thicknesses of 45 and 60 nm agreed well with those calculated from SPR theoretical equations. Morphology observations of the surfaces of deposited gold films on glass by atomic force microscopy (AFM) and a variation in resistance of the films with various thicknesses show the structure of the gold films. We concluded that the thin deposited gold films have many defects, and that the core of the gold-deposited optical fiber leaks light through the defects to the sample solution with the same refractivity (1.462 RI units) as that of the core.     

Quantitative characterization of the optical properties of absorbing polymer films: Comparative investigation of the internal reflection intensity analysis method

Nondestructive, three‐dimensional refractive‐index measurements are used for the determination of both the crystallinity and orientation in thin polymer films. The prism wave‐guide coupler is particularly suited for three‐dimensional isotropic and anisotropic thin‐film studies because of the quantitative character of the information obtained and the ease of data acquisition. It has been limited, however, to determining only the refractive index of transparent or weakly absorbing thin‐film samples. On the basis of thin‐film optics, this study develops a new internal reflection intensity analysis (IRIA) method, which uses the intensity information rather than the conventional mode angle values to acquire both the refractive index and the extinction coefficient over a range of transparent to highly absorbing polymer films. Therefore, the IRIA method overcomes the limitations of this prism wave‐guide coupler technique, which can only measure the refractive index of a weakly absorbing sample. With a Metricon PC‐2010 as the skeletal framework, a prototype instrument has been developed to apply and test the IRIA method. A study comparing both the refractive index and extinction coefficient obtained with ellipsometry, ultraviolet–visible/near‐infrared reflectometry, and IRIA for solvent blue 59 dyed polystyrene films confirms that the IRIA method is effective for obtaining the three‐dimensional refractive indices and extinction coefficients of polymer films. In addition, the refractive index and extinction coefficient spectrum (400–800 nm) of solvent blue 59 have been determined with the effective media theory. Furthermore, the three‐dimensional complex refractive indices of highly absorbing black electrical tape, inaccessible to other optical measurement because of its surface character, has been determined by the IRIA method. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 842–855, 2003     

PVA薄膜光波导气敏元件及其应用研究

将纯聚乙烯醇(PVA)和掺有维生素C的PVA作为敏感试剂,通过旋转甩涂法分别研制出了PVA薄膜/锡掺杂玻璃光波导元件和VC-PVA薄膜/锡掺杂玻璃光波导元件并检测其气敏特性.实验结果表明,PVA薄膜/锡掺杂玻璃光波导元件对二甲苯气体有良好的选择性响应,其响应浓度范围为10-4～10-7(体积比);加入VC后,使此敏感元...     

Application of a surface plasmon resonance sensor to analyses of amine compounds with the use of a polymer film and an acid-base reaction.

A surface plasmon resonance (SPR) sensor was applied to analyses of some amine compounds (n-butylamine, isobutylamine, aniline, and N,N-dimethylaniline) by using a polymer film and an acid-base reaction in it. Poly(acrylamide) (PAA) was adopted as the polymer film and was immobilized on an Au film to prepare a sensor chip. Pivalic acid was entered into the PAA film as an acid. The PAA film with a thickness of 50 nm gave the highest sensitivity to the SPR sensor. Although water was better concerning the sensitivity for the SPR sensor as the solvent, ethanol was adopted because it dissolves well all of the amine compounds used. The Au film coated with the PAA film gave higher sensitivity for analyses of n-butylamine and isobutylamine, and lower sensitivity for analyses of aniline and N,N-dimethylaniline than an Au film without the PAA film. The PAA film containing pivalic acid gave 4-5 orders of magnitude higher sensitivity to the SPR sensor for analyses of all the amine compounds due to the reaction between pivalic acid and these amine compounds.     

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.     

Surface plasmon sensor based on the enhanced light transmission through arrays of nanoholes in gold films

Arrays of nanoholes in a gold film were used to monitor the binding of organic and biological molecules to the metallic surface. This technique is particularly sensitive to surface binding events because it is based upon the resonant surface plasmon enhanced transmission through the array of nanoholes. The sensitivity was found to be 400 nm per refractive index unit, which is comparable to other grating-based surface plasmon resonance (SPR) devices. The array of nanoholes is well suited for dense integration in a sensor chip. Furthermore, the optical geometry is collinear, which simplifies the alignment with respect to the traditional Kretschmann (reflection) arrangement for SPR sensing.     

基于金银合金薄膜的高灵敏度宽光谱表面等离子体共振成像传感器

报道了一种基于金银合金薄膜的宽光谱表面等离子体共振成像(SPRI)传感器,该传感器能够对吸附在薄膜局部或整个表面上的生化分子进行原位定量检测,而且与常规的金膜SPRI传感器相比,检测成本更低,检测灵敏度更高。利用质量比1:1的金银合金溅射靶在玻璃基板上淀积了厚约50 nm的均匀的金银合金薄膜。利用实验室自制的Krestchmann结构多功能平台在不同入射角下测试了金银合金薄膜被纯水覆盖后的SPR光谱和SPR彩色图像。基于色相算法计算获得了每个SPR彩像的二维色相分布及其平均色相,从而使得宽光谱SPRI传感器能够利用平均色相作为灵敏度参数进行定量检测。实验确定了平均色相对溶液折射率(RI)变化和分子吸附最为敏感的光谱区间是595–610 nm之间。在这个窄光谱范围内,平均色相与共振波长呈线性关系,其斜率为?hue/?λR=7.52 nm~(-1),这意味着基于色相的RI灵敏度是基于共振波长的RI灵敏度的7.52倍,这一结论已被实验证明。将SPRI传感器的起始共振波长设定在色相敏感光谱区间内之后,实验测得基于色相的RI灵敏度为S=29879 RIU~(-1),比在相同条件下测得的金膜SPRI的灵敏度高8倍。利用时间分辨宽光谱SPRI方法实时监测了牛血清白蛋白(BSA)分子在金银合金薄膜表面的非特异性吸附,从实验测得的平均色相随时间的变化曲线可知BSA吸附达到平衡所需时间约15 min。研究结果表明,基于金银合金薄膜的SPRI传感器具有动态定量检测蛋白质分子吸附过程的功能。     

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.     

Detection of parathion methyl using a surface plasmon resonance sensor combined with molecularly imprinted films

An ultra-sensitive and highly selective parathion methyl(PM) detection method by surface plasmon resonance(SPR) combined with molecularly imprinted films(MIF) was developed. The PM-imprinted film was prepared by thermo initiated polymerization on the bare Au surface of an SPR sensor chip.Template PM molecules were quickly removed by an organic solution of acetonitrile/acetic acid(9:1,v/v), causing a shift of 0.58 in SPR angle. In the concentrations range of 10à13–10à10mol/L, the refractive index showed a gradual increase with higher concentrations of template PM and the changes of SPR angles were linear with the negative logarithm of PM concentrations. In the experiment, the minimum detectable concentration was 10à13mol/L. The selectivity of the thin PM-imprinted film against diuron,tetrachlorvinphose and fenitrothion was examined, but no observable binding was detected. The results in the experiment suggested that the MIF had the advantages of high sensitivity and selectivity.     

Optical detection of Cu ion using a SQ-dye containing polymeric thin-film on Au surface

In this study, we have fabricated Cu²⁺ ion sensor using a squarylium dye (SQ-dye) containing polymeric thin-film. Surface Plasmon Resonance (SPR) was used as a signal amplifier to achieve high sensitivity and large linear dynamic range for detection of Cu²⁺ ion. High selectivity to Cu²⁺ ion was obtained by the effective electro-static interaction between SQ-dye and Cu²⁺ ion in the polymeric film. The optimal analytical condition of high selectivity and sensitivity in the wider linear dynamic range obtained in this study may be a result of the cooperative ‘hard-soft’ metal ion-ligand interaction and effective detection of refractive index changes by the complexation of Cu²⁺ ion and SQ-dye in SPR measurement. Among 10 different alkali metal, alkaline earth metal, and transition metal ions, SQ-dye in poly(vinylchloride)–poly(vinyl acetate)–poly(vinyl alcohol) (PVC–PVAc–PVA) copolymer film showed the highest selectivity to Cu²⁺ ion. Although the interaction between SQ-dye and metal ions has not been well understood, both cooperative ‘hard-soft’ metal ion-ligand interaction and size-selective recognition of Cu²⁺ ion to SQ-dye may contribute to high selectivity. Furthermore, additional sensitivity in the detection of Cu²⁺ ion by SPR was obtained by matching the wavelength of probing radiation of SPR and absorption maximum of SQ-dye at 675 nm, which allow to detect small changes in the refractive index by complex formation on the sensing surface. This result may apply in development of the Cu²⁺ ion selective sensor for medical, biochemical, and environmental applications.     

Refractive index of thin, aqueous films between hydrophobic surfaces studied using evanescent wave atomic force microscopy

We have studied the refractive index of a thin aqueous film between microscopic hydrophobic surfaces using evanescent wave atomic force microscopy (EW-AFM). An evanescent wave, generated at a solid-liquid interface, is scattered by AFM tips or glass particles attached to AFM cantilevers. The scattering of this wave is used to determine the refractive index as a function of separation between these surfaces. Measurements were performed on surfaces that were rendered hydrophobic with octadecyltrichlorosilane, which produces solid-water contact angles in excess of 90 degrees. For AFM tips, the average refractive index in the thin film was always equal to that of water when the film was thicker than approximately 100 nm. At smaller separations, the refractive index was always greater than or equal to that of water. This is inconsistent with the formation of air or vapor films and consistent with a small amount of organic material between the surfaces. For colloidal spheres (R approximately 10 microm), we were not able to detect changes in the refractive index of the thin film between the sphere and plate.     

Application of polypyrrole/GOx film to glucose biosensor based on electrochemical-surface plasmon resonance technique

A surface plasmon resonance (SPR) based biosensor for glucose is presented in which a thin gold film modified with polypyrrole and glucose oxidase (PPy-GOx) acts as the sensor chip. It is based on SPR response to the change of refractive index of PPy-GOx film by the enzymatic catalytic reaction. The co-electropolymerization of pyrrole and GOx was carried out under cyclic voltammetric conditions, and simultaneously monitored by in-situ SPR. It has been revealed that the enzymatic reaction between GOx and PPy in the presence of glucose can lead to distinct changes in the SPR signal. From the experiments, a linear relationship was obtained in the range 1–100 μmol L^?1 between glucose concentration and the rate of redox transformation of PPy. The detection limit was 0.5 μmol L^?1 (S/N?=?3) and recoveries were 95.2–102.7%.     

Polyaniline thin film optical waveguides for integrated optics and VLSI prepared by vacuum evaporation technique

Polyaniline is emerging as an important polymer material which offers challenging opportunities for both fundamental research and new technological applications in waveguides. Metal doped polyaniline has been prepared initially in the form of powder by a solution growth technique. The emeraldine salt with doped metal was also prepared by solution growth technique. This powder was used for vacuum evaporation on optically flat glass substrate. The dark green doped (Fe, Al) polyaniline thin films were prepared by vacuum evaporation technique (10^?4 torr). Deposited waveguide thin films have been characterized structurally, using X‐ray diffraction (XRD), optically etc. Effective refractive index of the thin film waveguide was also calculated theoretically and experimentally. Waveguide parameters, namely refractive index, propagation loss and depth of vacuum deposited polyaniline thin films optical waveguide have been determined. The optical spectra and structure and waveguide parameters of vacuum deposited polyaniline thin films are strongly affected by the type of doping. It is possible to reduce the losses by addition of Fe to the vacuum deposited polyanine thin film and modify the effective refractive index (O_eff) according to particular requirements. Results are compared with the results in the literature. Copyright © 2002 John Wiley & Sons, Ltd.