KGN-PEG-MAL/SilMA/CNC composite hydrogel as a scaffold for chondrogenic differentiation of adipose-derived mesenchymal stem cells

An injectable KGN-PEG-MAL/SilMA/CNCs composite hydrogel was developed, in which KGN-PEG-MAL is physically incorporated within a photocrosslinked silk methacrylate (SilMA) network reinforced by cellulose nanocrystals (CNCs). The hydrogel provides enhanced mechanical stability, biocompatibility, and sustained chondrogenic stimulation, promoting adipose-derived stem cell (ADSC) differentiation and glycosaminoglycan (GAG)/type II collagen (COL II) matrix deposition in vitro and in vivo. This bioactive hydrogel offers a promising alternative to autologous cartilage grafts for nasal cartilage regeneration. • We developed an injectable composite hydrogel based on methacrylated silk fibroin reinforced with cellulose nanocrystals and incorporating polyethylene glycol–modified kartogenin (KGN-PEG-MAL) via physical entrapment. • The hydrogel combines enhanced mechanical stability with controlled drug release, enabling effective stimulation of stem cell differentiation toward cartilage. • In vitro and in vivo experiments demonstrated high biocompatibility, abundant glycosaminoglycan production, and collagen type II deposition, supporting its potential for cartilage tissue repair. Nasal cartilage defects often require grafting, but donor site morbidity and limited autologous supply remain major challenges. In this study, we developed a functional composite hydrogel based on photo-crosslinked silk methacrylate (SilMA) physically incorporated with cellulose nanocrystals (CNCs) and polyethylene glycol–modified kartogenin (KGN-PEG-MAL). The silk-based backbone provided photocurability, cellulose nanocrystals reinforced mechanical stability, and the modified kartogenin enabled controlled release and stimulation of stem cell chondrogenesis. In vitro, the hydrogel supported adipose-derived stem cell proliferation and migration, while enhancing chondrogenic differentiation, as confirmed by Alcian blue staining and increased expression of SOX9, ACAN, and COL2A1. In vivo, biocompatibility and matrix deposition were verified in a subcutaneous rat model, and chondrogenic regenerative capacity was further confirmed in a standard orthotopic cartilage defect model. These results demonstrate that the composite hydrogel provides a biocompatible and mechanically stable microenvironment capable of promoting hyaline-like cartilage formation. Designed for nasal cartilage regeneration, this hydrogel system shows translational potential as an alternative to autologous cartilage grafts in reconstructive applications.