Facile fabrication of silk fibroin microspheres via electrostatic assembly

Silk-based microsphere received remarkable attentions due to its impressive biocompatibility and biodegradation in drug delivery system. However, its application was still limited by complex process and unfriendly chemical agents using. In this study, we developed a novel approach to prepare silk fibroin nano or microspheres rapidly via electrostatic assembly. We demonstrated experimentally that the silk fibroin microsphere (SFM) with diameters ranging from 0.5 μm to 3 μm could be easily fabricated by combining pH value adjustment and low voltage electrostatic field. The production was optimized to be a simple and highly repeatable process that did not require sophisticated equipment and chemical agents. SFM represented α-helix structure enriching and homogeneous morphology, as well as improved dispersion and controllable size by regulating the silk fibroin concentration. The SFM demonstrated concentration-dependent drug release behavior with about 75% accumulative release ratio at day5. Thus, this SFM with high production efficiency and promise features provided a new drug carrier and substitute in control release field.