Regenerated silk fibroin based on small aperture scaffolds and marginal sealing hydrogel for osteochondral defect repair

Abstract

Abstract Background Osteochondral defects pose an enormous challenge with no entirely satisfactory repair strategy to date. In particular, the lateral integration of neocartilage into surrounding native cartilage is a difficult and inadequately addressed problem that determines the success of tissue repair. Herein, a novel design of an integral regenerated silk fibroin (RSF)-based three-layer scaffold combined with a self-setting RSF sealant for osteochondral repair is reported. Methods Regenerated silk fibroin (RSF) based on small aperture scaffolds was prepared with n-butanol innovatively. Then, the rabbit knee chondrocytes and bone mesenchymal stem cells (BMSCs) were cultured on RSF scaffolds, and after induction of chondrogenic differentiation, cell-scaffold complexes strengthened by RSF hydrogel were prepared for in vivo experiments. Results A porous small aperture scaffold and RSF sealant exhibiting biocompatibility and good adhesive properties were developed and confirmed to promote chondrocyte migration and differentiation. Importantly, small aperture scaffolds had a larger surface area accommodating more cells and contributed to higher intercellular communication and elastic modulus. An RSF hydrogel was conducted as a medium between the scaffolds and the native tissues and then guided new chondrocytes to crawl towards and replace the degraded materials from the surrounding cartilage. Thus, osteochondral repair and superior lateral integration were achieved in vivo with this composite. Conclusions Our results suggest that a new approach of marginal sealing around the RSF cartilage layer of small aperture scaffolds exhibits preeminent repair results as compared to other scaffolds, confirming the ability of this novel graft to facilitate simultaneous regeneration of cartilage-subchondral bone.