Three-dimensional cell spheroid technology: Recent advances and emerging strategies in cartilage regeneration.

Three-dimensional (3D) cell spheroid technology has led to significant advances in cartilage injury repair, the construction of osteoarthritis (OA) models, and the development of platforms for screening therapeutics targeting cartilage diseases. Compared with conventional two-dimensional (2D) cell culture, this technology better mimics the in vivo microenvironment, thus providing stronger support for cell growth and viability. Furthermore, it effectively stimulates chondrocytes proliferation and differentiation, facilitating cartilage tissue regeneration and significantly improving the quality and efficiency of cartilage regeneration. However, the clinical translation of this technology is hindered by several major challenges, including the limited long-term stability of cell spheroids, difficulties in large-scale production, and immune rejection following implantation in vivo. Advancements in materials science, machine learning (ML), and single-cell RNA sequencing (scRNA-seq) are expected to enable personalized and standardized 3D cell spheroid biofabrication. These advancements are likely to provide precise and efficient therapeutic solutions for cartilage regenerative medicine, thereby advancing cartilage regeneration and regeneration to unprecedented levels in translational applications. STATEMENT OF SIGNIFICANCE: Three-dimensional (3D) cell spheroid technology represents a significant advancement in cartilage regeneration due to its ability to mimic the native cartilage microenvironment, enhance cell-cell interactions, promote extracellular matrix production, and improve tissue repair outcomes. This review highlights recent developments in spheroid formation mechanisms, engineering strategies, and clinical applications. It also discusses key challenges such as large-scale production and immune safety, while exploring emerging solutions involving smart biomaterials and machine learning. This comprehensive summary provides broad insights into the translational potential of 3D cell spheroids for regenerative medicine. We believe this review may serve as a practical guide for biomaterials researchers.