紫外光照对锂藻土纳米粒子改性皮胶原多层次结构的影响

Effect of UV irradiation on the hierarchical structure of collagen fibers modified by Laponite clay nanoparticles

采用多种表征手段考察了紫外光照前后锂藻土纳米粒子(Laponite)改性皮胶原分子结构、聚集态结构和形态结构等多层次结构的变化.UV-visDRS、ATR-FTIR和WAXD分析结果表明,紫外光照可引起胶原分子间的氢键断裂和肽链上的氨基等活性基团的断裂而破坏其三股螺旋构象,而利用锂藻土纳米粒子改性可减缓紫外光照对胶原分子的光降解过程,降低紫外光照对皮胶原分子肽链结构、三股螺旋构象的影响.AFM和SEM观察显示,紫外光照可破坏胶原的原纤维周期性结构和纤维网络结构,而锂藻土纳米粒子改性可减少紫外光照对皮胶原原纤维周期性结构和纤维网络结构的影响.这些研究结果为深入理解锂藻土纳米粒子改性对皮胶原耐紫外光照性能的影响机制提供了理论基础.

In this work,conversions of hierarchical structure of collagen fibers modified by Laponite clay nanoparticles including molecular structure,aggregate structure and morphological structure under UV irradiation are investigated using multiple analysis approaches.UV-vis diffuse reflectance spectroscopy (UV-vis DRS),attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and wide angle X-Ray diffraction (WAXD) results show that disruptions of hydrogen bonds between collagen molecules and amino groups of polypeptide chains in collagen molecules occur under UV irradiation leading to destructions of trip-helical conformation of collagen molecules;whereas,under the same irradiation,the modification of Laponite can mitigate photo degradation of the collagen molecules without destroying their polypeptide chains and trip-helical conformation.Further atomic force microscopy (AFM) and scanning electron microscopy (SEM) observations reveal that D-periodic structure of fibrils and fiber networks are destroyed under the irradiation,but the collagen fibers modified with Laponite maintain their natural D-periodic structure without obvious changes of fiber networks.These findings can provide theoretical basis for further understanding the effect of modification of Laponite on the anti-UV property of collagen fibers.