Preparation and Properties of Silk Fibroin Microsopheres

In this study, a quickly and effective method to prepare well dispersivity microspheres has been reported. The isopropyl alcohol has been used as denaturant to process the fresh silk fibroin solution which can induce the formation of 13-sheets from random coil structure quickly, then the process of freezing had been used to induce the self-assembly of the 13-sheets silk fibroin macromolecules. The size and distribution of silk fibroin microspheres can be controlled by changing the molecular weight of silk fibroin macromolecules. The surface features were observed by scanning electron microscopy (SEM). The results indicated that the silk fibroin microspheres are spherical, the size and dispersvity of silk fibroin microspheres diameter were determined by article size analysis. The result showed that the diameter of silk fibroin microspheres prepared from LiBr solution at 90 degrees C decreased by 45.1% compared to 60 degrees C, with the distribution of the diameter ranging from 50 nm to100 nm, and the average value is 86.5 nm; the diameter of silk fibroin microspheres prepared from Cacl(2)/H2O/Et-OH solution at 100 degrees C decreased by 43.2% compared to 72 degrees C, and the diameter is 60-120 nm, the average value is 101.7 nm; the second structure of silk fibroin microsphere were investigated by Fourier Transform Infrared Spectroscopy (FTIR), the result suggested that the structure of silk fibrion molecule of microspheres has changed to beta-sheet or alpha-helix structure. In this way, the micro and nanospheres can be prepared quickly and effectively, which will largely broaden the applications of silk fibroin microspheres.