Comparative Assessment of Different Histidine-Tags for Immobilization of Protein onto Surface Plasmon Resonance Sensorchips

Surface plasmon resonance (SPR) is widely used to assess the kinetics and thermodynamics of binding of two molecules. The major challenge is immobilization of one molecule onto the sensorchip for robust detection of binding of the other molecule. We have compared a number of immobilization strategies for noncovalent attachment of an example protein (the substrate binding protein SiaP) by hexa-histidine (His), deca-His, and double-His tags to a nickel-nitrilotriacetic acid (NTA) surface. The stability of immobilization was assessed, and the binding of two low molecular weight ligands, Neu5Ac and 2-keto-3-deoxy-d-glycero-d-galacto-nononic acid (KDN), at different temperatures studied. The hexa-His tagged SiaP washed off from the surface too rapidly for ligand binding to be measured reliably. Systematic variation of chip loading identified conditions under which the deca-His tagged SiaP could generate reliable results. The double-His tagged protein performed as well as covalently attached deca-His tagged protein at 15, 25, and 35 °C. The observed ligand binding kinetics were comparable for all immobilization strategies, and thermodynamic values calculated from SPR are in agreement with solution-based isothermal titration calorimetry measurements. Extended trials suggest that covalent attachment is preferable for screening campaigns, whereas the double-His-tag strategy allows rapid regeneration of the chip, for example, when tight binding compounds are assessed.     

Exploitation of Localized Surface Plasmon Resonance

Recent advances in the exploitation of localized surface plasmons (charge density oscillations confined to metallic nanoparticles and nanostructures) in nanoscale optics and photonics, as well as in the construction of sensors and biosensors, are reviewed here. In particular, subsequent to brief surveys of the most‐commonly used methods of preparation and arraying of materials with localized surface plasmon resonance (LSPR), and of the optical manifestations of LSPR, attention will be focused on the exploitation of metallic nanostructures as waveguides; as optical transmission, information storage, and nanophotonic devices; as switches; as resonant light scatterers (employed in the different near‐field scanning optical microscopies); and finally as sensors and biosensors.     

差分表面等离激元共振传感仿真研究

从薄膜光学理论出发,对不同金属膜厚度、不同实折射率和不同复介电常数的环境介质的表面等离激元共振(SPR,Surface Plasmon Resonance)信号进行了分析,给出了最佳金属膜厚度,并且,折射率与共振角呈线性关系(R=0.999 4).分析了采用差分处理时,随环境介质的复介电常数变化的光反射率曲线.结果表明,同组两个探测器信号的和随环境介电常数的虚部变化,与实部无关,其信号差则相反,因此,能够同时测量环境介质的介电常数的实部和虚部.     

温度对表面等离子体振荡传感器的作用

本文采用棱镜型角度检测的方法,对表面等离子体振荡传感器进行精密检测.首先从理论上分析了温度对棱镜型表面等离子体传感器的作用机理,并根据机理进行了实验系统的设计.基于所设计的棱镜型角度检测SPR装置,研究了温度对表面等离子体振荡(SPR)共振角度的影响.实验给出了表面等离子体共振角度随被测液体温度的升高而下降的数值结果,斜率为-7.843×10-3/℃,并证明了温差控制对光传感技术中表面等离子体振荡(SPR)技术的实用化的重要性.     

贵金属纳米颗粒的表面等离子共振研究

通过修正的Mie理论分别对单金属Ag、单金属Cu和Cu核Ag壳纳米颗粒/玻璃复合材料的吸收光谱进行了理论计算.计算结果表明,对单金属Ag纳米颗粒/玻璃复合材料,Ag的吸收峰位于425nm左右,不随颗粒尺寸变化而发生偏移;对单金属Cu纳米颗粒/玻璃复合材料,Cu的吸收峰也不随尺寸变化发生偏移但强度较弱;对Cu核Ag壳纳米...     

光纤表面等离子体共振传感系统的数据处理

针对表面等离子体共振原理以及光纤传感的优越特性,本文提出并实现了一种基于光纤表面等离子体共振效应的传感检测系统,给出了系统数据分析的处理模型.该方法根据偏度-峰值检验,采用高斯分布检验对共振区域附近的测试数据进行了均值处理,通过理论分析进一步指出采用均值估计的线性模型可以有效地估计共振波长;同时,在保证检测精度的前提下给出了数据处理的最小运算长度.结果表明,可以使系统数据计算的工作量降低至原来的2%,从而提高了系统的处理效率.     

Probing Adsorption Behaviors of BSA onto Chiral Surfaces of Nanoparticles

Chiral properties of nanoscale materials are of importance as they dominate interactions with proteins in physiological environments; however, they have rarely been investigated. In this study, a systematic investigation is conducted for the adsorption behaviors of bovine serum albumin (BSA) onto the chiral surfaces of gold nanoparticles (AuNPs), involving multiple techniques and molecular dynamic (MD) simulation. The adsorption of BSA onto both L‐ and D‐chiral surfaces of AuNPs shows discernible differences involving thermodynamics, adsorption orientation, exposed charges, and affinity. As a powerful supplement, MD simulation provides a molecular‐level understanding of protein adsorption onto nanochiral surfaces. Salt bridge interaction is proposed as a major driving force at protein–nanochiral interface interaction. The spatial distribution features of functional groups (? COO^?, ? NH₃⁺, and ? CH₃) of chiral molecules on the nanosurface play a key role in the formation and location of salt bridges, which determine the BSA adsorption orientation and binding strength to chiral surfaces. Sequentially, BSA corona coated on nanochiral surfaces affects their uptake by cells. The results enhance the understanding of protein corona, which are important for biological effects of nanochirality in living organisms.     

表面等离子体共振生物传感器在食品安全检测中的应用与研究

表面等离子体共振（SurfacePlasmonResonance,SPR）传感技术是一项新兴的生物化学检测技术,具有无须标记、高速、高灵敏度等特点。日前在化学和生物检测研究中应用日益广泛。本文综述了SPR技术的基本原理及近年来在食品安全领域研究中取得的进展,并展望TSPR技术的发展方向及应用前景。     

基于局域表面等离子体共振效应生物传感器的制备方法及应用

金属纳米颗粒表现出来的局域表面等离子体共振效应被广泛应用于生物传感器领域.综述了局域表面等离子体共振效应的基本原理,对比了局域表面等离子体和表面等离子体的异同,详细介绍了胶体化学平板印刷术、电子束光刻法、聚焦离子束光刻法、纳米球光刻术等多种金属纳米颗粒阵列和图形制备技术、特点及应用,分析了局域表面等离子体共振生物传感器的应用前景、现存问题及其解决途径.     

金属纳米颗粒在表面等离激元共振生物传感器上的应用

文章研究不同形状和长径比的金属纳米颗粒应用在表面等离激元共振（SPR）生物传感器中对传感信号的影响,自制金属纳米颗粒并进行物理表征,以金纳米颗粒与抗兔IgG进行生物偶联,利用自制角度检测型SPR生物传感器对兔IgG抗体进行检测,结果表明,金属颗粒的形状和长径比对SPR传感器的共振角都有影响,金纳米棒能够明显提高SPR生物传感器的检测灵敏度。     

Ultra‐Smooth,Chemically Functional Silica Surfaces for Surface Interaction Measurements and Optical/Interferometry‐Based Techniques

The study of interfacial phenomena is central to a range of chemical, physical, optical, and electromagnetic systems such as surface imaging, polymer interactions, friction/wear, and ion‐transport in batteries. Studying intermolecular forces and processes of interfaces at the sub‐nano scale has proven difficult due to limitations in surface preparation methods. Here, we describe a method for fabricating reflective, deformable composite layers that expose an ultra‐smooth silica (SiO₂) surface (RMS roughness < 0.4 nm) with interferometric applications. The robust design allows for cleaning and reusing the same surfaces for over a week of continuous experimentation without degradation. The electric double‐layer forces measured using the composite surfaces are within 10% of the theoretically predicted values. We also demonstrate that standard chemisorption and physisorption procedures on silica can be applied to chemically modify the surfaces; as a demonstration of this, the composite surfaces are successfully modified with octadecyltrichlorosilane (OTS) to study their hydrophobic interactions in water using a surface force apparatus (SFA). These composite surfaces provide a basis for the preparation of a variety of new surfaces, and should be particularly beneficial for the SFA and colloidal probe methods that employ optical/interferometric and electrochemical techniques, enabling characterization of previously unattainable surface and interfacial phenomena.