用二维FTIR研究纳米TiO_2改性丝素蛋白聚集态结构转变

Two-dimensional FTIR correlation spectroscopic study on structure of nano-TiO_2 modified silk fibroin films

采用溶胶-凝胶方法制备纳米TiO2复合丝素膜。UV和SEM测试结果表明,该丝素膜中纳米TiO2均匀分散在丝素中,TiO2粒径约为80nm;同时采用一维红外光谱、二维红外相关光谱对纯丝素膜及复合丝素膜结构进行表征。结果表明,随着纳米TiO2的生成,丝素蛋白中弱氢键缔合的N—H键以及自由的N—H键发生断裂及重组,生成了强氢键;丝素分子从无序状态转变为有序排列,同时无规线团构象及α螺旋构象向β折叠构象发生转变,最后促使丝素蛋白的结晶构象从SilkⅠ转变为SilkⅡ。

Regenerated silk fibroin/nano-TiO2 composite films in different ratios were prepared by sol-gel method.UV-Vis spectroscopy and SEM observations revealed that the nano-TiO2 particles are well dispersed in the regenerated silk fibroin.Diameter of the nano-TiO2 particles was determined as about 80 nm.FTIR and two dimensional FTIR correlation spectroscopic studies indicated that the formation of nano-TiO2 particles leads to the aggregation structural changes of silk fibroin,in which strong hydrogen bonding was reconstructed from the rupture and rearrangement of the weak and free hydrogen bonding of the N-H groups. At the same time, the alignment of the silk fibroin molecules tends to be in an ordered form, and the crystal structure of fibroin in the composite films were transformed from Silk Ⅰ to a typical Silk Ⅱ form.