【作者】 王春刚；

【导师】 马占芳； 苏忠民；

【作者基本信息】 东北师范大学 ， 物理化学， 2007， 博士

【摘要】 生物分子与球形金纳米颗粒结合的杂化体系在生物分析和生物技术应用中都有着广泛的应用。DNA、抗原或抗体等生物分子功能化的金纳米颗粒在许多不同的生物传感体系中作为活性单元。球形纳米金颗粒能够被广泛应用在于它的表面可以简便有效的进行修饰,进而与生物分子偶联。近年来,各向异性（非球形）的金纳米颗粒,如金纳米棒,受到了人们的广泛关注。金纳米棒具有独特的可调控光学性质和几何结构,在生物分析中有着潜在的应用。但事实上,对金纳米棒与生物分子的杂化体系在生物分析中的应用没有得到广泛的研究,主要原因在于:（1）在合成金纳米棒过程中使用大量的表面活性剂,十六烷基三甲基溴化铵（CTAB）,且CTAB分子在金纳米棒表面吸附,生物分子很难与金纳米棒偶联,从而限制了在生物分析中的应用;（2）金纳米棒溶液中游离的大量CTAB分子对蛋白分子有毒性。基于以上两点,对金纳米棒进行表面修饰是其应用于生物标记必须解决的问题。此外,金纳米棒是很好的模板,可以构筑其它形状的金纳米结构。本论文主要从以下几个方面开展工作:（1）以不同比率金纳米棒做为晶种,通过改变反应介质的pH值可以很好的控制金纳米颗粒的形状。我们合成了长方形,“狗骨头”形,花生形,到粗糙表面的枝状金纳米结构。金纳米颗粒形状的改变直接影响它们的光学性质。（2）根据改进St?ber方法,可在不同比率棒状及狗骨头外形的具有各向异性的金纳米颗粒表面包覆二氧化硅外壳(Au_rod@SiO₂)。这种二氧化硅包金的复合纳米颗粒的二氧化硅外壳可以直接快速的组装到由聚4-乙烯吡啶（PVP）功能化的石英片表面。通过紫外可见光谱测定和肉眼观察,这种自组装膜在空气中干燥和重新浸湿反复循环过程中体现了高度可逆的光学变化和颜色变化特征。（3）基于Au_rod@SiO₂膜对蛋白质分子进行了比色检测。（4）在溶液中基于聚苯乙烯磺酸盐（PSS）修饰的金纳米棒生物探针的表面离子共振峰变化来快速敏感检测蛋白质。（5）制备了二氧化硅包埋金纳米棒的复合粒子(SiO₂@Au_rod@SiO₂)。利用SERS活性分子,对巯基苯胺,和SiO₂@Au_rod@SiO₂结合制备了一种新型免疫标记物,并且提出了一种结合表面增强拉曼和纳米粒子标记技术进行免疫检测的方法。采用固相抗体?抗原?标记SiO₂@Au_rod@SiO₂溶胶的“三明治”结构,借助抗体上标记SERS标签材料上的SERS信号达到单组分生物免疫检测的目的。更多还原

【Abstract】 Integrated biomolecule-spherical gold nanoparticle hybrid systems are widely used in bioanalysis and biotechnological applications. Spherical gold nanoparticles functionalized with biomolecules such as DNA or antigens （or antibodies） were employed as active units in many different biosensing systems. Because the surfaces of gold nanoparticles are easily and efficiently modified,as well as further conjugation with biomolecules.Recently, anisotropic gold nanoparticles （non-spherical shape） such as gold nanorods have attracted much attention. Because of the tunable optical properties and geometry, gold nanorods have promising potentialities in bioanalytical applications. However, in fact, the use of integrated biomolecule-gold nanorods hybrid system in bioaapplications has not been widely pursued. The main reasons exist as follows:（1） The presence of cetyltrimethylammonium bromide （CTAB） molecules adsorbed on the gold nanorod surface in addition to its use as a directing agent for gold nanorod synthesis. CTAB molecules are obstructive for displacing by the interest of biomolecules, which limit the further bioapplications;（2） The large amount of free CTAB molecules dispersed in the solution displays significant cytotoxicity for proteins.On the basis of the above facts, surface modification of gold nanorods is a key in order to label the biomolecules. In addition, gold nanorods can act as good template to construct various shapes of gold nanostructure. All the relative studies are outline as follows.（1） Fine control of gold nanoparticle shape can be achieved by varying the pH of the reaction medium in the presence of gold nanorods with different aspect ratio, which acted as seeds. Under various pH （3.6–9.6） values of the reaction medium, different shapes of gold nanostructural architectures, from rectangle-,“dogbone”- and peanut-like outlines to branched multipods with corrugated surface, can be fabricated in high yield. These shape changes of gold nanorods directly influence their opticalproperties.（2） Silica-coated anisotropic gold nanoparticles （Au@SiO₂）, including rod- and“dogbone”-like outlines with different aspect ratios, have been prepared using an improved St?ber method. The obtained Au@SiO₂ have a pure silica surface for straightforward and rapid self-assembly onto poly（4-vinylpyridine） （PVP） functionalized quartz substrates. The assemblies exhibit highly reversible optical changes that can be observed spectroscopically or with the naked eye when repeatedly cycled between a dry and wet process.（3） The colorimetric detection of protein has been achieved based on Au@SiO₂ film.（4） The surface of gold nanorods with functionalized by poly（styrenesulfonate） （PSS） for the attachment of protein yielded gold nanorod molecular probes, which exhibited the rapid and sensitive detection of protein by localized surface plasmon absorption （LSPR）.（5） Gold nanorods embedded into silica paricles (SiO₂@Au_rod@SiO₂) have been prepared. We used the comnbination the SERS active molecules, p-aminothiophenol, and SiO₂@Au_rod@SiO₂ to prepare a novel immunotag and propose an immunoassay detection method based on the combination of surface-enhanced Raman scattering （SERS） and the nnaoparticle labeling. Antibody immobilized on a glass slide/antigen/reporter-labeled SiO₂@Au_rod@SiO₂ sandwich assay was build for SERS measurements by SERS signal of p-aminothiophenol for detection of the single type biospecific species.更多还原