Silk Fibroin Spheres Crosslinked by Polyethylene Glycol Diglycidyl Ether for Drug Delivery

Silk fibroin (SF) has been widely investigated in biomedical applications due to its biodegradability and biocompatibility. The objective of this work was to prepare SF spheres for drug delivery application. Drug-loaded SF spheres with and without polyethylene glycol diglycidyl ether (PEGDE) crosslinking were prepared by a water-in-oil emulsion solvent diffusion method. Blue dextran was used as a water-soluble model drug. Effects of homogenizing speed and PEGDE ratio on characteristics and drug release behaviors of the SF spheres were determined. All of the SF spheres were nearly spherical in shape. The particle size of SF spheres decreased as the homogenizing speed increased. The PEGDE crosslinking can induce SF conformational transition from random coil to β-sheet form and increase drug loading efficiency. In vitro drug release content decreased as the particle size and PEGDE ratio increased. The results suggested that the desired drug release profiles of SF spheres can be tailored by adjusting the particle size and PEGDE ratio.