表面等离子体共振传感技术应用于小分子检测

人体内的生物小分子对维持生命体健康具有重要影响,此类分子参与生命体的血液循环及免疫系统,因此检测生命体中生物小分子对研究小分子在生命体中的生理功能有着重要的意义.傅里叶变换-表面等离子体共振(Fourier transform-surface plasmon resonance,FT-SPR)光谱技术具有操作简便、灵敏...     

用表面等离子体共振传感器检测纳米间距

结合物理光学原理和表面等离子体共振（SPR）角度传感器,提出了可以突破衍射极限的纳米间距检测方法。在理论上建立起纳米间距和位相改变量之间的函数关系,借助于SPR角度传感器的高灵敏性,提出通过检测出射光束振动方向的p分量和s分量的位相差值来实现纳米间距的实时检测。模拟结果显示：纳米间距改变量从-0.5～0.5μm变化时,位相改变量可实现-150°～150°的变化,检测灵敏度〉1 nm。该检测方法能够实现10 nm以下间距的灵敏检测,且具有结构简单,易于操作,实时检测的特点。     

利用纳米金局域表面等离子体共振散射方法检测痕量汞(Ⅱ)

在Britton-Robinson(BR)(pH为9.0)缓冲介质中,微量Hg(Ⅱ)离子能诱使被巯基乙酸钠包被的AuNPs发生聚集,以此诱发局域表面等离子体共振(localized surface plasmon resonance, LSPR)散射峰的出现,随着Hg(Ⅱ)浓度的不断增加,体系在548 nm的LSPR散射信号显著增强,其散射强度与Hg(Ⅱ)的浓度具有相关性,且在0.08～0.8 μmol·L-1范围内呈现一定的线性关系,由此构建了以Hg(Ⅱ)为目标分析物的LSPR散射分析检测方法,检测限为8 nmol·L-1。研究了体系的LSPR散射光谱以及吸收光谱,利用扫描电镜考察了AuNPs与Hg(Ⅱ)反应前后粒径的变化情况,发现单独的AuNPs呈现良好的分散状态,当加入Hg(Ⅱ)后,AuNPs呈现聚集状态。同时探讨了体系反应机理,结果表明Hg(Ⅱ)的加入与AuNPs表面的羧基发生螯合作用诱导了AuNPs的聚集。考察了体系对金属离子Hg(Ⅱ)的选择性,实验中选择了一系列的金属离子与AuNPs作用,其结果表明Hg(Ⅱ)与AuNPs作用的LSPR散射信号增强效果最为明显,而其余离子即使在浓度较高时其LSPR散射强度依然较弱,说明了实验设计方案对Hg(Ⅱ)具有优异的选择性。此外,研究了体系酸度,离子强度以及稳定剂对体系的影响。实验所建立起来的方法操作简单,分析速度快速,检测灵敏度较高。该方法已经成功用于环境水样中痕量Hg(Ⅱ)的检测。     

基于狭缝扫描的表面等离子体共振成像

利用表面等离子体共振技术进行电介质样品成像研究.采用高数值孔径显微物镜作为耦合元件,632.8nm He-Ne激光会聚激发金膜产生表面等离子体共振,通过狭缝光阑限制光束入射角,对金膜上的氮化硅光栅进行成像.反射光由放置在样品像方共轭面上的CCD摄像机接收,获得样品的表面等离子体共振像.通过扫描移动狭缝,得到入射角从44°至54°的扫描样品图像,从图像中提取样品各点的表面等离子体共振曲线,由计算机重构出样品的表面等离子体共振角谱灰度图.     

基于分光计的表面等离子体共振实验

在分光计的基础上,利用激光二极管作为光源,自制硅光电池放大电路作为检测元件,自行组装了角度指示型表面等离子体共振传感器综合实验装置.使用该装置可以在分光计上观察表面等离子体共振现象,测量电解质折射率与共振角的关系.     

表面等离子体共振与表面增强拉曼散射相关性研究

本实验利用实验室搭建的SPR-SERS显微拉曼光谱仪同时检测了吸附在40 nm银膜上的4-amin-othiophenol(4-ATP)自组装膜的表面等离子体共振(Surface Plasmon Resonance,简称SPR)消光谱及表面增强拉曼散射(Surface-Enhanced Raman Scattering,简称SERS)光谱,研究了两者之间的相关性。实验发现随着SPR吸收的增强,SERS强度也急剧增强,在SPR共振角附近SERS强度是远离共振角处的20多倍。因此在共振角附近能够极大的提高SERS的检测灵敏度并扩展SERS的应用。     

表面等离子体共振成像生物芯片检测系统

根据表面等离子体共振(Surface Plasmon Resonance, SPR)原理,提出基于表面等离子体共振成像(Surface Plasmon Resonance imaging, SPRI)的生物芯片检测系统构建方法.介绍了SPRI生物芯片检测系统的原理、自行组建的SPRI生物芯片检测系统的结构.采用Kretschmann型棱镜耦合结构激励SPR,偏振的平行光经棱镜投射到生物芯片上,发生表面等离子体共振,由CCD摄像机采集反射光芯片图像.以巯基修饰淋病奈瑟氏菌探针为例验证该系统,利用自组装单分子层技术(Self-Assembled Monolayer,SAM)固定探针.应用该检测系统采集了探针共振、非探针处共振、探针和非探针处都不共振时的生物芯片图像.     

光纤表面等离子体共振传感检测系统共振波长的红移

介绍了光纤表面等离子体共振传感器的制造工艺和系统组成,针对光纤传感检测系统在一定的条件下进行了多次测试,试验表明该系统在测试过程中存在红移现象.分析了发生红移的主要原因是金属薄膜内部和表层吸附了空气中的杂质.为此提出了改进镀膜工艺、测试条件和建立修正数据库已有效地减弱了系统测试中的红移现象.     

表面等离子体共振技术的一些新应用

介绍了表面等离子体共振技术在表面等离子体共振传感器、扫描近场光学显微技术、薄膜光学和膜厚测量、全息成像技术、Q开关、精密角度测量等领域的新应用.     

光纤SPR湿敏传感器及其共振光谱特性研究

提出并研制了基于光纤SPR传感探针的新型湿敏传感器。首先研究了光纤SPR传感探针对环境湿度变化的敏感特性,在此基础上提出在光纤SPR传感探针表面增覆不同厚度且具有水分子吸附功能的PVA薄膜来实现环境相对湿度的监测。研究结果表明,增覆双层PVA薄膜的光纤SPR传感探针在高湿区具有较好监测效果,其共振强度对应的相对湿度测量灵敏度达到1.59%/%RH,较光纤SPR探针呈现显著提高。而增覆单层PVA薄膜的光纤SPR传感探针在高湿区共振波长对应的相对湿度监测灵敏度达到2.411nm/%RH。此外所提出的新型光纤SPR湿敏探针在PVA薄膜失效后经过特殊工艺处理仍可重复镀膜使用。     

Novel Design of Sagnac Interferometry Assisted with Surface Plasmon Resonance Based Sensor Technique

In this work, we demonstrate a novel design to investigate interfacial reaction of optical activity materials, utilizing a Sagnac interferometer assisted with surface plasmon resonance based sensor technique. Upon application to interrogate optical activity, the type-2 optical configuration of close loop in this work can entirely encircle the interaction zone of surface plasmon resonance reacting with optical activity medium, while the type-1 optical configuration of close loop does partially. The greater the geometrical phase owing to the encircled interaction zone between optical activity medium and polarized light, the larger the phase shift of interference pattern modulated by the concentration of optical activity medium. The slope of phase shift in interference phase pattern of p-wave vs. concentration of dextrose solution determined with this method is greatly improved, 3000 times better than that with Lee's method, 18,600 times with Lin's method, and 222,000 times with Chou's method. Besides, the pinch point of phase shift vs. concentration indicates the ending of interference pattern phase shift as the concentration of each tested optical activity medium keeps climbing up, and can reflect the strong dependence of molecular shape during interfacial adsorption.     

费米折射率平面波导激励的差分检测型对称结构表面等离子共振传感研究

为了实现被测折射率范围可调,提高检测灵敏度,将双波长差分检测技术应用于平面波导激励的金属-介质-金属组成的对称型表面等离子体共振传感结构中.通过对对称结构的模式特性分析,研究了该结构中激发等离子体表面波时,介质厚度与被测折射率的关系及双波长差分检测的原理.采用离子交换法制备平面波导,用费米函数拟合其渐变折射率分布.用光强调制方式,分别进行单波长和双波长差分检测,对折射率为1.33~1.428之间的甘油溶液进行测试,实验结果表明,该结构可激发等离子体表面波,与传统平面波导激励的表面等离子体共振传感结构相比,通过改变被测介质的厚度可以改变共振条件,进而改变折射率的测量范围.若被测范围选择合适,检测的线性较好,采用差分检测方法比单波长检测方法的灵敏度提高近一倍.     

(p,n)和(p,2n)反应激发函数的系统学研究

从普朗克(Planck)黑体辐射公式和实验测量数据出发,采用唯象的方法提出了包含两个可调参量,入射质子能量从阈能到150MeV,靶核质量数在44相似文献   

Measurement of thicknesses and optical properties of thin films from Surface Plasmon Resonance (SPR)

The inverse problem for thin film properties is a challenge for nanotechnology engineering. We propose the application of a simple and intuitive numerical scheme: a basic particle swarm optimization (PSO) method, to solve the inverse problem from surface plasmon resonance (SPR) experimental results. The purpose is to retrieve unknown parameters from the measurement of the fall in reflectivity due to the excitation of a surface plasmon polariton at a metal/dielectric interface. In this case, the PSO results reveal the possibility of fully exploring the measurement results of experimental angular exploration of the reflectivity by multilayers.     

Localized Surface Plasmon Resonance of Cu@Cu2O core-shell nanoparticles: Absorption, Scattering and Luminescence

By co-deposition via RF-Sputtering and RF-PECVD methods and using Cu target and acetylene gas, we prepared Cu@Cu₂O core-shell nanoparticles on the a-C:H thin film at room temperature. Mie absorption of Cu cores, scattering from Cu₂O shell and luminescence that rises from carrier transfer in Cu@Cu₂O interface were employed to fit the whole range of visible extinction spectrum of these core-shells. From simulation it was found that scattering and luminescence have an important effect on the energy, width and shape of LSPR absorption peak. Shift of LSPR peak is more affected by the dielectric coefficient of shell than Cu core size particularly for Cu core diameter above 4 nm. Also, the LSPR absorption peak is damped by decreasing Cu core size and dielectric coefficient of shell. The energy of LSPR absorption peak is independent of shell thickness and host dielectric coefficient. The LSPR peak is damped by increasing shell thickness and host dielectric coefficient too. The scattering contribution in extinction spectra was affected more by shell size than dielectric coefficient. These points are important for detection techniques based on LSPR peak.     

Propagation Characteristics of Surface Plasmon Polaritons Near Anisotropic 2D Materials Sandwiched by Chiral Media

A novel surface plasmonic waveguide structure composed of chiral medium and 2D material is proposed. The universal direction-dependent dispersion relation is obtained, which covers the combinations between 2D materials with in-plane isotropy or anisotropy and the surroundings with or without chirality. The tunability of the behavior of surface plasmon polaritons with the chirality of environment and the doping level are investigated. The averaging effect of chirality in both sides of 2D material is unveiled. Besides, the transverse spin of SPPs in the Chiral-2D material structure is explored and the asymmetric distribution of the transverse spin depends mainly on the contribution from the magnetic spin instead of the electric spin. These features are advantageous for the manufacture of novel photonic devices and the development of sensors techniques for the chiral environment.     

Third-Order Nonlinear Optical Response near the Plasmon Resonance Band of Cu_(2-x)Se Nanocrystals

The third-order nonlinear optical properties of water-soluble Cu_(2-x)Se nanocrystals are studied in the near infrared range of 700-980 nm using a femtosecond pulsed laser by the Z-scan technique. It is observed that the nonlinear optical response of Cu_(2-x)Se nanocrystals is sensitively dependent on the excitation wavelength and exhibits the enhanced nonlinearity compared with other selenides such as ZnSe and CdSe. The W-shaped Z-scan trace, a mixture of the reversed saturated absorption and saturated absorption, is observed near the plasmon resonance band of Cu_(2-x)Se nanocrystals, which is attributed to the state-filling of free carriers generated by copper vacancies(self-doping effect) of Cu_(2-x)Se nanocrystals as well as the hot carrier thermal effect upon intense femtosecond laser excitation. The large nonlinear optical response and tunable plasmonic band make Cu_(2-x)Se nanocrystals promising materials for applications in ultra-fast all-optical switching devices as well as nonlinear nanosensors.     

光谱、波谱法研究铜锌超氧歧化酶与氯化钴(Ⅱ)、组氨酸钴(Ⅱ)相互作用

我们首次发现的铜锌超氧歧化酶（Ｃｕ２Ｚｎ２ＳＯＤ）与氨基酸等发生直接相互作用的现象,是一种前人未研究过的重要的生化新现象［１］。在此新发现的基础上,本文用ＩＣＰ,ＶＩＳ,ＮＭＲ和酶活性测定等方法,又从不同角度拓展研究了Ｃｕ２Ｚｎ２ＳＯＤ酶与两类不同化合物,即无机氯化钴（ＣｏＣｌ２）、有机组氨酸钴（Ｃｏ（Ⅱ）（Ｈｉｓ）ｎ）的直接相互作用,发现酶活性中心金属离子同样与外加的这两类不同化合物发生相互作用,相应地影响了酶的催化活性。还发现Ｃｏ（Ⅱ）（Ｈｉｓ）ｎ比ＣｏＣｌ２与酶相互作用更强、更快,Ｃｏ（Ⅱ）（Ｈｉｓ）ｎ中的Ｃｏ（Ⅱ）更易进入酶中,更影响了酶的催化活性。     

氦原子(n1sn2p)组态能级的相对论修正

本文采用拉卡基函数并借助不可约张量理论,导出氦原子(n1sn2p)组态的各种相对论效应的理论计算式,在这一过程中,完成了所有的角向积分和自旋求和计算,其结果用径向矩阵元形式来表示.     

MDM2与抑制剂PDIQ作用机制的结合自由能计算研究

p53-MDM2之间的相互作用是抗癌药物设计的重要靶标。采用分子动力学模拟和结合自由能计算研究抑制剂PDIQ与MDM2的结合模式,结果显示范德华作用是二者结合的主体力量。基于残基的自由能分解计算结果表明CH-CH、CH-π和π-π相互作用驱动了二者的结合。这一研究成果可为抗癌药物的设计提供理论上的指导。