纳米银/丝素复合材料的制备及其光谱性质研究

开发可靠、生态友好的纳米材料合成方法是当今纳米技术发展的一个重要方面，基于天然生物材料如丝素蛋白原位合成来制备纳米贵金属溶胶是一种具有极大发展潜力的方法之一。文章在室温下以丝素原位还原硝酸银制得了纳米银/丝素复合溶胶，通过紫外-可见光谱、原子力显微镜、荧光光谱和共振光散射对其制备过程和光谱性质进行了表征。实验表明丝素链中的酪氨酸残基对AgNO₃还原生成纳米银颗粒起了主要作用，制得的纳米银粒子均匀地包埋在丝素胶体中，具有很好的分散性和稳定性，可长期保存。丝素蛋白与纳米银复合后，荧光强度明显增加，证明了丝素蛋白与纳米银表面之间形成了较强的化学吸附，在银表面形成了一个相对稳定的络合物致密层。同时利用共振散射光谱分析实验进一步证实了纳米银粒子的形成。

Preparation and Spectroscopic Studies of Nanosilver/Silk-Fibroin Composite

The development of reliable, eco-friendly processes for the synthesis of nanomaterials is an important aspect of nanotechnology today. One approach that shows immense potential is based on the in situ synthesis of noble metal nanocolloids using natural biological material such as silk fibroin. In the present paper, the nano-Ag/silk-fibroin colloids were prepared by in situ reducing AgNO3 with silk-fibroin at room temperature without any reducing agent. UV-Vis absorption, atomic force microscopy, fluorescence spectra and resonance scattering spectra were used to study the preparation process and characterization of the nanocomposite. It was found that the formative Ag nanoparticles were attributed to the tyrosine residues in the chains of silk-fibroin that act as reduction agent in the reduction course of AgNO3, and the Ag nanoparticles were uniformly embedded in silk-fibroin colloid, which possess good dispersity and stability and can be kept for a long period. The strength of fluorescence spectra increased after reaction of silk-fibroin with AgNO3 solution, showing that there was a strong chemical adsorption between silver nanoparticles and silk-fibroin, and a stable complex layer was formed in silver nanoparticales. Meanwhile the existence of silver nanoparticles in silk-fibroin was proved by resonance scattering spectra.