Injectable biomimetic hydrogel based on modified chitosan and silk fibroin with decellularized cartilage extracellular matrix for cartilage repair and regeneration.

Cartilage defect repair remains a challenge for clinicians due to the limited self-healing capabilities of cartilage. Microenvironment-specific biomimetic hydrogels have shown great potential in cartilage regeneration because of their excellent biological properties. In this study, a hydrogel system consisting of p-hydroxybenzene propanoic acid-modified chitosan (PC), silk fibroin (SF) and decellularized cartilage extracellular matrix (DCM) was prepared. Under the catalysis of horseradish peroxidase (HRP), the phenol hydroxyl groups on PC and SF were crosslinked to form a hydrogel. DCM incorporation into the hydrogel facilitated an emulation of the natural cartilage extracellular matrix. The synthesized injectable hydrogels could fill irregular defects and formed network structures that promoted cell adhesion and proliferation. In vitro experiments demonstrated that the hydrogels had biocompatibility and promoted chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). The DCM-derived hydrogel exhibited low immunogenicity in vivo, and in the treatment of both rabbit trochlear groove cartilage defects and goat femoral condyle cartilage defects, the hydrogel accelerated the cartilage regeneration. In summary, our developed composite hydrogel system in the study offers a potential strategy for the effective repair of cartilage defects.