【作者】 吴超；

【导师】 胡家文；

【作者基本信息】 湖南大学 ， 生物医学工程， 2009， 硕士

【摘要】 金纳米颗粒有着独特的光学性质,在医学、传感、分析化学等方面有很好的应用前景,近年来成为人们研究的热点。在本论文中,我们针对金纳米颗粒性质进行了三方面的研究。(1)使用还原法和优化后的种子法,制备了一系列不同粒径的金纳米颗粒,并比较了两种制备方法的优缺点。这为后面研究金纳米颗粒的表面修饰与光谱学性质奠定了基础。(2)对金纳米颗粒进行了表面修饰,获得了很好的性能。金纳米颗粒由于纳米颗粒的粒径小,比表面积大,且微粒间范德华力作用的存在,使得颗粒间易于团聚。将线性α-甲氧基-ω-巯基聚乙二醇(mPEG-SH, 5000 MW)通过巯基化学吸附于金溶胶表面,可形成高分子层包被的金溶胶。研究结果表明,PEG修饰的金溶胶可以在pH = 1~13.5和盐浓度高达1.20 mol/L的较苛性条件下保持稳定。这是由于金溶胶表面吸附的高分子保护层为溶胶提供了新的空间稳定。因而,PEG保护的金溶胶在很大程度上克服了对环境敏感、易聚沉的缺点,能在复杂的条件(如生理条件)下应用。鉴于PEG的水溶性、无毒性和生物亲和性,这种具有较高稳定能力的金纳米粒子/PEG复合体结合了金纳米粒子和PEG的优异性能,可作为生物纳米探针用于复杂条件下的生物分析。(3)把表面修饰功能分子的金纳米颗粒用于pH传感器研究。我们在金纳米颗粒表面依次修饰上信号功能分子4-巯基吡啶及线性α-甲氧基-ω-巯基聚乙二醇。研究结果表明,修饰后的金纳米颗粒不仅能够在强酸、强碱和高浓度盐溶液中稳定存在,而且依然保持了较好的pH传感器的性能,分散在一系列pH值的缓冲溶液中时,对pH值有很好的响应。这些优良的性质为以后将金纳米颗粒基底的pH传感器运用于复杂条件下的生物分析,奠定了一定基础。更多还原

【Abstract】 With unique optical properties, gold nanoparticles have promising prospects in medical, sensing, analytical chemical, which have become a hot topic in recent years. In this thesis, gold nanoparticles have been investigated from three dimensions.Firstly, a series of gold nanoparticles with controllable diameters were prepared via reduction and an improved seed-mediated technique respectively. Comparison between these two methods was made, which laid a foundation for latter investigations, such as surface modification and spectroscopy property of gold nanoparticles.Secondly, We modified the surface of gold nanoparticles, and got excellent properties. Gold nanoparticles are tending to aggregate for their small diameter , large surface ratio and van der waals force. Linearα-methoxy-ω-mercapto-poly (ethylene glycol) molecules were chemically bonded to gold particle surfaces via the end group, SH, forming polymer brush-coated gold colloids. Experimental results indicate that the PEG-modified gold nanoparticles can resist aggregation under rigorous conditions of pH=1~13.5 or salt concentration as high as 1.20 mol/L, because the adsorbed PEG layer provides steric stabilization for the gold nanoparticles. Therefore, the PEG layer-coated gold nanoparticles largely solve the problems associated with nanoparticles, such as susceptivity to environment conditions and easiness in aggregation, and can survive in complex conditions (e.g. physiological conditions).Because of the water soluble, nontoxic, and biocompatible properties of PEG, the gold nanoparticle/PEG conjugated with high stability and excellent properties of both gold nanoparticles and PEG can serve as bio-nanoprobes for bio-analysis.Thirdly, we applied the gold nanoparticles to PH sensor. We modified successively the signals and PEG on the surface of gold nanoparticles, which then be tested. Experimental results show that the PEG-modified gold nanoparticles can resist aggregation under rigorous conditions of pH=1~13.5 or salt concentration as high as 1.20 mol/L, moreover they maintain preferable performance. Even dispersed in a series of PH buffer solution, the gold nanoparticles are sensitive to PH value. All the excellent properties lay a foundation for applying PH sensor of the gold nanoparticles to complicated bioanalysis.更多还原