Natural silk nanofibrils as reinforcements for the preparation of chitosan-based bionanocomposites.

Nanofibrils derived from natural biopolymers have received extensive interest due to their exceptional mechanical properties and excellent biocompatibility. To fabricate biocompatible chitosan nanocomposites with high mechanical performance, silkworm silks were deconstructed into nanofibrils as structural and mechanical reinforcement of chitosan. After dispersing silk nanofibrils in chitosan solution, a set of nanocomposites, including film, porous scaffold, filament, and nanofibrous sponge, could be fabricated from the blended solutions. Silk nanofibrils could be uniformly dispersed in chitosan solution, and formed multi-dimensional nanocomposites. The nanocomposites exhibited enhanced mechanical strength and thermal stability, and provided a biomimetic nanofibrous structure for biomaterial applications. The enhancement in mechanical properties can be attributed to the interaction between the nanofibril phase and the chitosan matrix. As the polysaccharide/protein bionanocomposites derived from natural biopolymers, these materials offer new opportunities for biomaterial application by virtue of their biocompatibility and biodegradability, as well as enhanced mechanical properties and controllable mesoscopic structure.