小波变换和神经网络在化学中的应用

本论文分为两部分：小波变换和神经网络在化学中的应用。小波变换是新近出现的数学方法。近年来，在化学中得到广泛的应用，本论文介绍小波变换和我分辨分析的原理和方法，并将其应用到信号的压缩和滤噪。在研究中提出了常用小波变换数据压缩的三种方法，将紧支集小波和正交三次B－样条小波压缩4－苯乙基邻苯二甲酸酐的红外光谱数据进行了对比，计算表明正交三次B－样条小波变换方法效果较好，而在全部保留模糊信号及只保留锐化信号中数值较大的系数时，压缩比大而重建光谱数据与原始光谱数据间的均方差较小。应用小波变换对表面等离子体子共振（Surface Plasmon Resonance，SPR）仪的信号进行滤噪处理，利用SPR仪器信号和噪音的频率特性而将其分离，取得良好效果。本文对神经网络在化学中应用进行了较深入的研究，并对影响神经网络的诸多因素进行了探讨。在神经网络和多元回归等在化学应用中过多的变量会导致数学模型的预测结果变差，因而选择合适变量是很重要的。本文对比了传统的统计方法（前进选择法，后退剔除法，逐步回归法），Leaps-and-Bounds回归法，正交变换法，主成分分析以及最新的优化技术遗传算法，得到了一些有意义的结果。同时提出了组合算法和前进选择法的得合算法，结果表明这种算法在一定程度上避免了局部最优且减少了计算量。本论文还利用上述方法进行了一些定量结构活性相关性研究，主要内容：1）环境中有毒有害有机物（苯酚，苯胺，硝基苯）的定量结构活性相性研究。2）抗艾滋病类药物（HEPT）定量结构活性相关性研究。3）抗肿瘤类药物（氮芥子气类化合物和2－甲酸吡啶缩氨基硫脲类化合物定量结构活性相关性研究。4）苯酚和苯胺类衍生物色谱比移值预测。5）将神经网络用于茶叶的分类。

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。

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.

Layer-by-layer assembly of biologically inert inorganic ions/DNA multilayer films for tunable DNA release by chelation

In this work, we illustrate a simple chelation-based strategy to trigger DNA release from DNA-incorporated multilayer films, which were fabricated through the layer-by-layer (LbL) assembly of DNA and inorganic zirconium (IV) ion (Zr4+). After being incubated in several kinds of chelator solutions, the DNA multilayer films disassembled and released the incorporated DNA. This was most probably due to the cleavage of coordination/electrostatic interactions between Zr4+ and phosphate groups of DNA. Surface plasmon resonance (SPR), UV-vis spectrometry and atomic force microscopy (AFM) were used to characterize the assembly and the disassembly of the films.

Electrodissolution of Inorganic ions/DNA Multilayer Film for Tunable DNA Release

A layer-by-layer film composed of DNA and inorganic zirconium ion (Zr4+) was fabricated on the surface of gold thin film, and an electric field triggered disintegration of the multilayer film was studied by using electrochemical surface plasmon resonance (EC-SPR). EC-SPR results demonstrated that the film was disassembled upon the application of an electric field and the disassembly rate varied with the applied potential, leading to the controlled release of DNA. The electrodissolution could be switched off by removing the electric potential and reactivated by reapplying the potential.

Enzyme Colorimetric Assay Using Unmodified Silver Nanoparticles

Colorimetric assay based on the unique surface plasmon resonance properties of metallic nanoparticles has received considerable attention in bioassay due to its simplicity, high sensitivity, and low cost. Most of colorimetric methods previously reported employed gold nanoparticles (GNPs) as sensing elements. In this work, we develop a sensitive, selective, simple, and label-free colorimetric assay using unmodified silver nanoparticle (AgNP) probes to detect enzymatic reactions. Enzymatic reactions concerning adenosine triphosphate (ATP) dephosphorylation by calf intestine alkaline phosphatase (CLAP) and peptide phosphorylation by protein kinase A (PKA) were studied.

A new method for studying the interaction between chlorpromazine and phospholipid bilayer

The spectroscopic and transmission electron microscopy (TEM) studies of interaction between chlorpromazine (CPZ) and dimyristoyl phosphatidylglycerol (DMPG) bilayer by using gold nanoparticles (AuN-Ps) as probes are reported. The DMPG bilayer-protected AuNPs were prepared by a simple one-step method. The DMPG bilayer tethered on the AuNPs was considered as a biomembrane model. The addition of CPZ affected the surface plasmon resonance (SPR) and morphology of the prepared AuNPs, and this effect was monitored by UV-vis spectroscopy and TEM.

Environmentally friendly synthesis of highly monodisperse biocompatible gold nanoparticles with urchin-like shape

We report a facile and environmentally friendly strategy for high-yield synthesis of highly monodisperse gold nanoparticles with urchin-like shape. A simple protein, gelatin, was first used for the control over shape and orientation of the gold nanoparticles. These nanoparticles, ready to use for biological systems, are promising in the optical imaging-based disease diagnostics and therapy because of their tunable surface plasmon resonance (SPR) and excellent surface-enhanced Raman scattering (SERS) activity.

Seed-Mediated Growth of Nearly Monodisperse Palladium Nanocubes with Controllable Sizes

Nearly monodisperse Pd nanocubes with controllable sizes were synthesized through a seed-mediated growth approach. By using Pd nanocubes of 22 nm in size as seeds, the morphology of the as-grown nanostructures was fixed as single-crystalline, which enabled us to rationally tune the size of Pd nanocubes. The formation mechanism of initial 22 nm nanocubes was also discussed. The size-dependent surface plasmon resonance properties of the as-synthesized Pd nanocubes were investigated. Compared with previous methods, the yield, monodispersity, perfection of the shape formation, and the range of size control of these nanocubes are all improved.