Silk Fibroin Microspheres: Preparation and Application for Controlled Drug Delivery

Silk fibroin( SF),a natural protein polymer,has several unique properties such as aqueous processability,biocompatibility,and biodegradability.Due to these advantageous properties,it is promising for applications in various fields,especially drug delivery.In this paper, the simple preparation of SF microspheres was discussed via self-assembly.Some of SF’s physicochemical properties and morphology were also investigated.The results show that the morphology,size and size distribution of silk microspheres depend upon various processing parameters, especially including volume ratios among SF,ethanol and polyvinyl alcohol( PVA).Regular silk microspheres were obtained in PVA solution when adjusting the volume ratios of silk to ethanol from 20 ∶ 1 to 20 ∶ 9.We also found that SF microspheres with various appearances were formed by addition of different PVA solution concentrations under a constant silk solution to ethanol volume ratio.From the Fourier transform infrared spectroscopy( FTIR) of silk microspheres,it was found that introducing ethanol into the SF solution induced conformational change from random coil to β-sheet.Additionally, under the observation of scanning electron microscopy( SEM),the shape of self-assembled silk microspheres was determined to be spherical.Finally,SF’s potential as drug delivery carriers was discussed in the experimental results.