Feng Xin-Xing, Guo Yu-Hai, Chen Jian-Yong, Zhang Jian-Chun
The State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065, P. R. China.
J Biomater Sci Polym Ed. 2007;18(11):1443-56. doi: 10.1163/156856207782246786.
By sol-gel processing, regenerated nano-TiO2/SF (silk fibroin) composite films were synthesized. The experimental results revealed that the nano-TiO2 particles were well dispersed in the regenerated silk fibroin. Using FT-IR and Raman spectroscopy, the secondary structures of these composite films with concentrations of 0, 0.2, 0.4, 0.8 and 1.6 wt% were characterized. Concentration-perturbed two-dimensional (2D) correlation spectra were calculated for the spectra in the 1800-1600 cm(-1) region. To investigate nano-TiO2 particles induced changes in the secondary structure and hydration, the slice spectra were calculated from the synchronous and asynchronous spectra, respectively. The transmittance IR and Raman spectra measurement indicated that the secondary structure of the pure silk film was mostly random coil and alpha-helix, while the composite films were beta-sheet. With increasing nano-TiO2 content, the secondary structure of composite films was changed from typical Silk I to typical Silk II. However, it was found that the transition of the SF's secondary structures would be restrained by excessive nano-TiO2 (over 0.8%) introduced into the composite SF films. Through the FT-IR absorbance and 2D correlation spectra, it was demonstrated that the formation of nano-TiO2 particles could induce the partial transformation of SF conformation from Silk I to Silk II.
通过溶胶-凝胶法制备了再生纳米TiO₂/丝素蛋白（SF）复合薄膜。实验结果表明，纳米TiO₂颗粒在再生丝素蛋白中分散良好。利用傅里叶变换红外光谱（FT-IR）和拉曼光谱对浓度分别为0、0.2、0.4、0.8和1.6 wt%的这些复合薄膜的二级结构进行了表征。计算了1800 - 1600 cm⁻¹区域光谱的浓度扰动二维（2D）相关光谱。为了研究纳米TiO₂颗粒引起的二级结构和水化变化，分别从同步光谱和异步光谱计算了切片光谱。红外光谱和拉曼光谱的透射率测量表明，纯丝素薄膜的二级结构主要是无规卷曲和α-螺旋，而复合薄膜为β-折叠。随着纳米TiO₂含量的增加，复合薄膜的二级结构从典型的丝I转变为典型的丝II。然而，发现引入复合丝素薄膜中的过量纳米TiO₂（超过0.8%）会抑制丝素二级结构的转变。通过FT-IR吸光度和二维相关光谱表明，纳米TiO₂颗粒的形成可诱导丝素构象从丝I部分转变为丝II。
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