丝素蛋白/聚乙二醇薄膜结构性质和药物释放研究

Structural regulation of silk fibroin/PEG blend films for controlled drug release

以溶液浇注法制备丝素蛋白/聚乙二醇(PEG)混合薄膜,利用傅里叶红外光谱(FT-IR)和差示扫描量热(DSC)分析薄膜材料结构的变化及对其力学性能和溶解性的影响,并以罗丹明B为模型药物构建药物缓释体系,分析罗丹明B从混合薄膜中释放的动力学,探讨利用PEG调节丝素蛋白材料的药物释放性能的可能性。结果显示,PEG与丝素蛋白具有良好的相容性,在作为增塑剂的同时引起丝素蛋白由无规卷曲向β-折叠结构的转变,可以在不同程度上调节混合薄膜的力学性能、耐水性和药物缓释性能。随着PEG含量的增加,丝素蛋白/PEG混合薄膜的拉伸强度和断裂延长率先增加后减小,分别于CPEG为10%和20%附近达到最大值,而在水中的溶失率的变化规律与拉伸强度刚好相反,在CPEG为10%附近达到最小值。与纯丝素蛋白薄膜相比,添加PEG极大延缓了药物模型分子罗丹明B的释放。罗丹明B的释放属于非典型Fickian扩散机理,混合薄膜中丝素的silkⅡ结晶和非结晶区域具有不同的药物释放特征,增加PEG添加量造成罗丹明B释放常数k的下降和扩散指数n的增加。

Blend films were prepared from silk fibroin （SF） and polyethylene glycol （PEG） using a solution casting method, and the structural change of blend films were investigated form infrared spectroscopy （FF-IR） and differential scanning calorimetry （DSC）. by Fourier transThe results were utilized to reveal the influence of PEG addition on the mechanical and dissolution properties of the blend films and the release kinetics of Rhodamine B, a model compound loaded in the SF/PEG matrix, with the purpose to regulate the drug releasing property of SF biomaterial by blending with PEG. It was found that PEG was compatible with SF and capable of inducing conformational transition of SF from random coil to β-sheet, resulting in changes in mechanical and dissolution properties, as well as drug release feature of the blend films. With increasing PEG content, the tensile strength and elongation of blend films first increased and then decreased, reaching a maximum around 10% and 20%, respectively. On the contrast, the dissolution of blend films first decreased and then increased, reaching a minimum around 10%. Compared with the pure SF film, addition of PEG greatly reduced the release of Rhodamine B. It was suggested that Rhodamine B released from SF! PEG blend films via a non-typical Fickian diffusion mechanism, of which the release constant k de- creased and diffusion parameter n increased with increasing PEG content, maybe due to the different releasing feature of the silk II crystalline and noncrystalline region of SF.