摘要Background:Cartilage repair remains a considerable challenge in regenerative medicine.Despite extensive research on biomaterials for cartilage repair in recent years,issues such as prolonged repair cycles and suboptimal outcomes persist.Organoids,miniature three-dimensional(3D)tissue structures derived from the directed differentiation of stem or progenitor cells,mimic the structure and function of natural organs.Therefore,the construction of cartilage organoids(COs)holds great promise as a novel strategy for cartilage repair.Methods:This study employed a digital light processing system to perform 3D bioprinting of a DNA-silk fibroin(DNA-SF)hydrogel sustained-release system(DSRGT)with bone-marrow mesenchymal stem cells(BMSCs)to construct millimeter-scale CO.COs at different developmental stages were characterized,and the COs with the best cartilage phenotype were selected for in vivo cartilage repair in a rat articular cartilage defect model.Results:This study developed a DSRGT by covalently grafting glucosamine(which promotes cartilage matrix synthesis)and TD-198946(which promotes chondrogenic differentiation)onto a hydrogel using acrylic acid-polyethylene glycol-N-hydroxysuccinimide(AC-PEG-NHS).In vitro,4-week COs exhibited higher SRY-box transcription factor 9(SOX9),type Ⅱ collagen(Col Ⅱ),and aggrecan(ACAN)expression and lower type Ⅰ collagen(Col Ⅰ)and type Ⅹ collagen(Col Ⅹ)expression,indicating that 4 weeks is the optimal culture duration for hyaline cartilage development.In vivo,the mitogen-activated protein kinase(MAPK)signaling pathway was upregulated in 4-week COs,enabling cartilage repair within 8 weeks.Transcriptomic analysis revealed that cartilage regenerated with 4-week COs presented gene expression profiles resembling those of healthy cartilage.Conclusion:This study employs DSRGT to construct COs,providing an innovative strategy for the regeneration of cartilage defects.