Fabrication of silk microcapsules by layer-by-layer desolvation

Abstract

The procedure to increase shell thickness of multilayer silk microcapsules fabricated by layer-by-layer assembly (LbL assembly) are tedious and time-consuming. To address this, layer-by-layer desolvation (LbL desolvation), a more efficient technique, was developed with PLGA microspheres as sacrificial templates. Due to high efficiency of desolvation in increasing the shell thickness, self-supporting structures were obtained with merely seven silk layers. Permeability of the microcapsules was manipulated with high efficiency as well. Moreover, crosslinking was found to reduce surface charge of the shell. We attributed this to crosslinking-induced conformational change of silk fibroin based on secondary structure analysis. The LbL desolvation technique will facilitate fabrication of multilayer silk microcapsules for biomedical applications.