Australian Future Fibers Research and Innovation Centre, Deakin University, Vic 3217, Australia.
Biomacromolecules. 2012 Aug 13;13(8):2503-12. doi: 10.1021/bm300736m. Epub 2012 Jul 12.
The aim of this study was to understand the structure and biodegradation relationships of silk particles intended for targeted biomedical applications. Such a study is also useful in understanding structural remodelling of silk debris that may be generated from silk-based implants. Ultrafine silk particles were prepared using a combination of efficient wet-milling and spray-drying processes with no addition of chemicals other than those used in degumming. Milling reduced the intermolecular stacking forces within the β-sheet crystallites without changing the intramolecular binding energy. Because of the rough morphology and the ultrafine size of the particles, degradation of silk particles by protease XIV was increased by about 3-fold compared to silk fibers. Upon biodegradation, the thermal degradation temperature of silk increased, which was attributed to the formation of tight aggregates by the hydrolyzed residual macromolecules. A model of the biodegradation mechanism of silk particles was developed based on the experimental data. The model explains the process of disintegration of β-sheets, supported by quantitative secondary structural analysis and microscopic images.
本研究旨在了解针对生物医学应用的靶向丝颗粒的结构和生物降解关系。这样的研究还有助于了解可能由丝基植入物产生的丝状碎片的结构重塑。采用高效的湿法研磨和喷雾干燥工艺制备超细丝颗粒，除了脱胶过程中使用的化学品外，没有添加其他化学物质。研磨降低了β-片晶内的分子间堆积力，而不改变分子内结合能。由于颗粒的粗糙形貌和超细尺寸，丝颗粒的蛋白酶 XIV 降解速度比丝纤维提高了约 3 倍。在生物降解过程中，丝的热降解温度升高，这归因于水解后的残留大分子形成了紧密的聚集体。根据实验数据，建立了丝颗粒生物降解机制的模型。该模型通过定量的二级结构分析和微观图像解释了β-片层解体的过程。
