表面等离子体共振技术研究生物分子相互作用

本论文利用表面等离子体共振技术（sPR）进行了生物分子间相互作用的研究。主要包括可免疫识别、免疫分析、生物分子相互作用动力学以及层层组装生物分子功能膜等方面的研究。1．利用表面等离子体共振生物传感器对血清中HSA抗体的活性进行了检测。结果表明表面等离子体共振（SPR）生物传感器能快速实时检测anti-HSA抗体的活性，且传感片能够重复使用100次以上。2．应用表面等离子体共振生物传感器实现了对铁蛋白的实时免疫分析。实验中采用"三明治"放大法提高了分析的灵敏度和选择性。结果表明，在血清中分析铁蛋白的线性区间为30-200ng/ml，检测限为28ng/ml。应用pH2.0 glycine-HCl溶液进行再生，传感片可重复使用50次以上。3．通过溶液竞争法实现了S尸R技术对小分子化合物吗啡的检测。结果表明，溶液竞争法大大优于表面竞争法。同时求得了吗啡、mBSA与单抗及多抗之间相互作用的结合常数，并进行了比较。对实验现象给出了动力学上的合理解释。4．研究了通过静电吸附作用，DNA和PDDA交替组装多层膜。实时表面等离子体共振技术实时监测了DNA/PDDA多层膜的形成，研究了DNA在PDDA表面的吸附动力学。电化学阻抗谱和紫外可见光谱的研究结果也表明了这种层层组装多层膜的均一性。5．应用亲合素和生物素之间的强亲和作用，在金表面层层组装了由亲合素／生物素化抗体组成的蛋白质多层膜。使用实时BIA技术监测了多层膜的成膜过程，同时用电化学阻抗和傅立叶红外光谱对多层膜的成膜过程进行了表征。结果都表明了多层膜的均匀生长。同时，我们用亲和素生物素化抗体层层组装所制备的抗体多层膜对hlgG进行了灵敏检测。6．应用实时BIA技术研究了组蛋白与DNA之间的相互作用。发展了新的固定DNA传感片表面，消除了组蛋白与商品化传感片之间的非特异吸附。用Langmuir和Two State Reaction（Coormation change）模型对所得的动力学传感图进行了拟合，初步得到了动力学常数，直观的比较了组蛋白各亚组分与DNA相互作用之间的动力学差异。

纳米结构界面组装及电化学SPR研究

围绕论文题目“纳米结构界面组装及电化学SPR研究”，我们将SPR与电化学技术有机的结合起来，建立了电化学SPR（EC-SPR）技术，开展了相关的EC-SPR研究工作。同时，在一些特殊纳米结构的界面组装方面进行了创新研究。本论文研究工作的主要内容和创新点表现在以下几个方面：1．首次成功地将纳米粒子自组装膜模板与化学镀金技术相结合成功地用于湿化学法制备SPR响应基片，攻克国际上仅用物理法制备SPR镀金片的局限和困难，为SPR技术的进一步普及奠定了一定的基础。2．此外，还成功地将纳米粒子自组装膜模板与化学镀金技术相结合，制备了Au（III）单晶纳米岛阵列薄膜及电极。3．在国内率先将电化学和表面等离子体共振（SPR）光谱技术相结合，构建了EC-SPR仪器操作系统；并将此技术用于现场原位表征和研究导电聚合物薄膜和生物大分子（DNA和电活性蛋白质分子）纳米结构组装体的光电特性。4. 首次合成并报道了纳米粒子模板法制备中空的银／金表面钉状双金属纳米粒子，及其在水和空气界面受扩散受限聚集控制的二维介观分形聚集。丰富和拓展了纳米粒子二维分形聚集的研究。5．将欠电位沉积电化学方法拓展用于表面微加工。实验结果表明，对化学镀制备的多晶金SPR响应基片进行连续的银欠电位沉积与溶出电化学处理，不仅可以改善金膜表面的粗糙度，还能对表面的原子进行结构重排，使其具有An（III）的电化学响应特征；SPR信号对SPR响应金膜表面的原子排列非常灵敏。6．将欠电位沉积电化学法用于新颖的纳米催化剂设计，首次制备了铂原子单层沉积的纳米金单层膜并成功地用于4电子氧催化还原反应。大基于纳米受限环境下水的特殊性质（不挥发性）的启示，成功地进行了DDAB表面活性剂泡囊和环状多金属氧酸盐（POM）纳米簇的仿生超分子模板界面静电组装。

电化学SPR研究及形貌可控的纳米结构合成

围绕论文题目“电化学SPR研究及形貌可控的纳米结构合成”，我们将SPR传感膜同时用作电化学研究的界面，开展了相关的EC-SPR研究工作。同时，在一些可控纳米结构的合成与表征方面进行了创新研究。 本论文研究工作的主要内容和创新点表现在以下几个方面：1．生物分子模板生长法为构建具有特定功能的新颖材料提供了新的途径。报道了一种基于固定的DNA为模板通过电化学途径合成DNA-聚苯胺复合物的方法。在这种条件下，目标生物分子能保持其天然结构和生物活性，能用于构建功能多样性的导电聚合物结构。2．首次用溶液中溶解氧现场原位还原产生的活性氧中间体作氧化剂，在蒸镀的金膜电极上阴极极化合成聚苯胺（PANI）。聚苯胺膜的厚度可很容易地在分子水平的尺度上控制，其表面形貌对金膜表面层原子的结晶取向非常敏感。在多晶金电极上可得到岛型的纳米结构，而在单晶Au（111）电极上则聚合得到超薄膜。3．在金电极表面电化学聚合形成的导电聚合物聚吡咯（PPy）膜被用作双层磷脂 膜（BLMs）的新的支撑体。PPy膜支撑的双层脂膜的形成依赖于所用脂分子的化学结构，在一定程度上PPy膜支撑的双层脂膜类似于传统的双层脂膜结构，在脂膜结构的内外两侧保持着水介质环境。PPy膜支撑的双层磷脂膜可很方便地用于仿生膜研究。4．采用光刻法构建SPR阵列传感器的金膜点阵列，拟将来用于SPR成像分析。把正型光刻胶旋涂于SPR金片表面，紫外光通过自制掩模曝光后，用碱液显 影。然后采用选择性化学刻蚀暴露出的金膜，最后用剥离液去掉未曝光的光 胶层，从而构建所需的金膜点阵列，点的大小和间距可方便地由掩模来控制。用壳聚糖为例进行了金膜点阵列的表面修饰与组装。点阵列间的玻璃表面能 抑制亲水性和疏水性分子的吸附，这在SPR成像分析及高通量筛选方面将非常有用。5．在生物学上，生物大分子或有机体通常能调节及控制生物／无机杂化材料和晶 体的形貌及组装，这个过程被称为生物矿化。我们报导了基于生物小分子，L一氨基酸的金纳米结构的生物合成。在没有表面活性剂及硬模板存在下，天冬氨酸能直接还原氯金酸生成大量的厚度小于30nm的金纳米盘，该纳米盘为单晶结构，主要晶面为｛111｝，特征形貌为平均边长为590nm的对称六角形以及平均边长为840nm的去顶角三角形纳米晶体。6．苯胺及其衍生物作为模型化合物被用于有意图地构建金属纳米材料。苯胺还原氯金酸生成金核直径38nm壳gnm的核／壳结构的球形纳米粒子，3-氨基苯甲酸（3-ABA）调制生成厚度为20nm边长为105nm的形状规则的金纳米片，4一氨基苯甲酸（4-ABA）指导生成直径为18nm长度为微米级的纳米线结构，2一氨基苯磺酸（2-ABS）能调节生成直径为13．7nln长度可达几十微米的“之”字形的金纳米线，而1-（4-氨基苯基）乙二胺-N，N，N'，N'-四乙酸（4-ABEDTA）能还原氯金酸并相应控制生成结构完好由平均直径为19nm的金球形纳米粒子连接的线结构并进一步组织成纳米分形网络结构，表明苯胺环上取代基的种类和位置对金属纳米结构形貌的调节有直接影响。

TRANSMISSION ELECTRON-MICROSCOPY STUDY OF N+-IMPLANTED SILICON ON INSULATOR BY ENERGY-FILTERED IMAGING

We report on the first study of N+ -implanted silicon on insulator by energy-filtered imaging using an Opton electron microscope CEM 902 equipped Castaing-Henry electron optical system as a spectrometer. The inelastic images, energy window set at DELTA-E = 16 eV and DELTA-E = 25 eV according to plasmon energy loss of crystal Si and of silicon nitride respectively, give much structure information. The interface between the top silicon layer and the upper silicon nitride layer can be separated into two sublayers.

Collective excitations in coupled quantum wells

The dielectric response of a modulated three-dimensional electron system composed of a periodic array of quantum wells with weak coupling and strong coupling are studied, and the dispersions of the collective excitations and the single particle excitations as functions of wave vectors are given. It is found that for the nearly isolated multiple-quantum-well case with several subbands occupation, there is a three-dimensional-like plasmon when q(z)=0 (q(z) is the wave-vector component in the superlattice axis). There also exist intersubband collective excitations in addition to one intra-subband mode when q(z) not equal 0. The intra-subband mode has a linear dispersion relation with q(//) (the wave-vector component perpendicular to the superlattice axis) when q(//) is small. The inter-subband modes cover wider ranges in q(//) with increasing values of q(z). The energies of inter-subband collective excitations are close by the corresponding inter-subband single-particle excitation spectra. The collective excitation dispersions show obvious anisotropy in the 2D quantum limit. The calculated results agree with the experiment. The coupling between quantum wells affects markedly both the collective excitations and the single particle excitations spectra. The system shows gradually a near-three-dimensional electron gas character with increasing coupling. Copyright (C) 1996 Published by Elsevier Science Ltd

基于二维表面等离子体激元的微结构

在介电常数符号相反的两个材料的界面处可激发出表面等离子体激元（Surface plasmon)。文中利用普通扫描电子显微镜中出现的电子束诱导沉积纳米碳基本现象，提出和发展了一种无需光刻胶和额外掩模的亚微米图形化技术。采用这一新方法，成功地在镀金的半导体InGaAlP量子阱表面制备了各种亚微米点阵结构，并得到基于二维表面等离子体激元的可见波段半导体发光的增强作用。

Spatial Mode Selection by the Phase Modulation of Subwavelength Plasmonic Grating

The extraordinary transmission of the subwavelength gold grating has been investigated by the rigorous coupled-wave analysis and verified by the metal-insulator-metal plasmonic waveguide method. The physical mechanisms of the extraordinary transmission are characterized as the excitation of the surface plasmon polariton modes. The subwavelength grating integrated with the distributed Bragg reflector is proposed to modulate the phase to realize spatial mode selection, which is prospected to be applied for transverse mode selection in the vertical cavity surface-emitting laser.

Terahertz Quantum Cascade Laser Operating at 2.94 THz

The development of quantum cascade laser at 2.94 THz is reported. The laser structure is based on a bound-to-continuum active region and a semi-insulating surface-plasmon waveguide. Lasing is observed up to a heat-sink temperature of 70 K in pulsed mode with light power of 4.75 mW at 10 K and 1 mW at 70 K. A threshold current density of 296.5 A/cm(2) and an internal quantum efficiency of 1.57 x 10(-2) per cascade period are also observed at 10 K. The characteristic temperature of this laser is extracted to be T-0 = 57.5 K.

Surface Initiated Polymerization from Substrates of Low Initiator Density and Its Applications in Biosensors

Surface initiated polymerization (SIP) has become an attractive method for tailoring physical and chemical properties of surfaces for a broad range of applications. Most of those application relied on the merit of a high density coating. In this study we explored a long overlooked field of SIP. SIP from substrates of low initiator density. We combined ellipsometry with AFM to investigate the effect of initiatior density and polymerization time on the morphology of polymer coatings. In addition, we carefully adjusted the nanoscale separation of polymer chains to achieve a balance between nonfouling and immobilization capacities. We further tested the performance of those coating on various biosensors, such as quartz crystal microbalance, surface plasmon resonance, and protein microarrays. The optimized matrices enhanced the performance of those biosensors. This report shall encourage researches to explore new frontiers in SIP that go beyond polymer brushes.

Preparation and Optical Properties of Gold Nanowire Arrays

Gold nanowires with diameters (d) between,15 run and 200 urn and with length/diameter ratio of 700 were prepared in ion-track templates with electrode position method. The morphology and crystal structure of the gold nanowires were Studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The 200 nm (d) gold nanowires preferred orientation along the [100] direction were formed at the deposition voltage of 1.5 V (Without reference electrode). The optical properties of gold nanowire arrays embedded in ion-track templates were studied by UV-Vis spectrophotometer. There was a strong absorption peak at 539 nm for 45 nm (d) gold nanowire arrays. With the diameter of gold nanowires increasing, the absorption peak shifted to the longer wavelength. At last, the result was discussed combined with surface plasmon resonance of gold nanoparticles.

Controlled synthesis and diameter-dependent optical properties of Cu nanowire arrays

Using electrochemical deposition, Cu nanowire arrays have been successfully fabricated by home-made polycarbonate ion-track templates. The diameters were well controlled by etching time of templates. The minimum diameter is 15 nm. The morphologies and structures were analyzed by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The wires prefer [1 1 0] growth direction due to H ions absorption. The optical properties of Cu nanowire arrays are studied by an ultraviolet/visible/near-infrared spectrophotometer. Two extinction peaks were observed in spectra. The optical mechanism is discussed based on surface plasmon resonance

The annealing behavior of Cu nanoparticles in Ar-ion implanted spinel

Magnesium aluminate spinel crystals (MgAl2O4 (1 1 0)) deposited with 30 nm Cu film on surface were implanted with 110 key Ar-ions to a fluence of 1.0 x 10(17) ions/cm(2) at 350 degrees C, and then annealed in vacuum condition at the temperature of 500, 600, 700, 800 and 900 degrees C for 1 h, respectively. Ultraviolet-visible spectrometry (UV-VIS), scanning electron microscopy (SEM), Rutherford backscattering (RBS) and transmission electron microscopy (TEM) were adopted to analyze the specimens. After implantation, the appearance of surface plasmon resonance (SPR) absorbance peak in the UV-VIS spectrum indicated the formation of Cu nanoparticles, and the TEM results for 500 degrees C also confirmed the formation of Cu nanoparticles at near-surface region. In annealing process, The SPR absorbance intensity increased at 500 and 700 degrees C, decreased with a blue shift of the peak position at 600 and 800 degrees C, and the peak disappeared at 900 degrees C. The SPR absorbance intensity evolution with temperature was discussed combined with other measurement results (RBS, SEM and TEM). (C) 2010 Elsevier B.V. All rights reserved.

Enhanced nucleation of Ag nanoparticles by vacancy-type defects in Ar-ions implanted spinel

Vacancy-type defects are introduced into magnesium aluminate spine] (MgAl2O4 (1 1 0)) by Ar-ions implantation, and then Ag-ions are implanted into the depth rich in vacancy-type defects. The ultraviolet-visible spectrometry (UV-VIS) and positron annihilation spectroscopy (PAS) are used to study the influence of vacancy-type defects on nucleation of Ag nanoparticles. After introduction of vacancy-type defects the pronounced increase of surface plasmon resonance (SPR) absorbance intensity indicates that defects enhance the nucleation of Ag nanoparticles. The PAS results reveal that vacancy-type defects provide pre-nucleating centers for Ag nanoparticles nucleation and growth. (C) 2010 Elsevier B.V. All rights reserved.

Enhanced resonance light scattering based on biocatalytic growth of gold nanoparticles for biosensors design

The biocatalytic growth of gold nanoparticles (Au-NPs) has been employed in the design of new optical biosensors based on the enhanced resonance light scattering (RLS) signals. Both absorption spectroscopy and transmission electron microscopy (TEM) analysis revealed Au-NP seeds could be effectively enlarged upon the reaction with H2O2, an important metabolite that could be generated by many biocatalytic reactions.