金纳米粒子-胱氨酸三维网状结构的形成及其光谱特性研究

用柠檬酸三钠还原法制备了水溶性金纳米粒子, 粒子的平均粒径为4.5 nm, 它与胱氨酸作用后, 胱氨酸利用双硫键在其表面成功地进行了自组装, 获得了金纳米粒子-胱氨酸的三维网状结构. 用紫外-可见光谱、光散射光谱、透射电子显微镜等手段对胱氨酸组装前后的金纳米粒子进行了表征. 结果显示, 粒子与粒子之间, 通过静电引力形成了离子键, 吸收光谱变化明显, 金纳米粒子特征吸收峰由组装前518 nm红移到670 nm, 溶液颜色也相应由酒红色变为蓝紫色, 求出了金纳米粒子-胱氨酸三维网状结构形成过程中胱氨酸的最佳量, 金与胱氨酸的物质的量比为1∶1. 对于4.5 nm的金纳米粒子, 只有14%左右的胱氨酸在金纳米粒子的表面进行了自组装, 而多余的86%的胱氨酸未与金纳米粒子作用; 其共振瑞利散射光谱具有潜在的应用价值. 该研究对以金纳米粒子为基础的新材料制备进行了有益的探索.

Preparation and Spectrometric Characteristics of Three Dimension Net Structure Made of Gold Nanoparticle and Cystine

A water-soluble gold nanoparticle was prepared with trisodium citrate by reduction method, and using cystine as a self-assembled molecule, three dimensional net structure of gold nanoparticle with cystine was obtained. Various techniques, such as UV-Vis spectrophotometry, transmission electron microscopy, Religh light-scattering spectrum, were used to characterize gold nanoparticle and the 3D net structure. The average diameter of gold nanoparticle assembled by cystine in this 3D net structure was about 5.1 nm, bigger than that of gold nanoparticle of 4.5 nm. In order to form 3D net structure, the optimal molar ratio of gold to cystine was 1∶1, and a pH 5.1 buffer solution of sodium citrate-citric acid was required. Only approximate 14% of cystine molecules was assembled to surface of gold nanoparticle, while excessive cystine played an important role in the 3D net structure, where cystine molecule was a bridge among gold nanoparticles and ion band was a dominating factor. Compared with gold nanoparticle (518 nm), its UV-Vis absorption peak has been red-shifted to 670 nm and such 3D net structure had a nonlinear light-scattering characteristics.