High-performance cartilage tissue bioink for 3D bioprinting with minimal post-processing for articular cartilage regeneration.

Abstract

Despite recent advances, clinical translation of articular cartilage remains limited. This is primarily due to engineering challenges and safety issues associated with extensive post-printing steps, including the reliance on exogenous growth factors and cross-linking agents. To overcome these limitations, we developed a high-performance cartilage Tissue bioink incorporating porcine synovium-derived mesenchymal stem cell (pSMSCs) mesenchymal condensation process augmented by decellularized cartilage extracellular matrix (DCECM) to facilitate intrinsic chondrogenesis without additional biochemical cues. The Tissue bioink exhibited a homogeneous distribution of pSMSCs and DCECM, with increase in cartilage-specific ECM components. Proteomic analysis further demonstrated increased cartilage ECM components and pathways associated with matrix remodeling and chondrogenesis via TGF-β1/SMAD signaling axis. Rheological analysis confirmed that the bioink exhibited shear-thinning behavior and rapid recovery of structural integrity, ensuring stable printability. Optimized printing parameters supported high cell viability. After 14 days of culture without growth factors or cross-linking agents, the printed constructs exhibited a twofold increase in sulfated glycosaminoglycan and collagen deposition, further validating their ongoing chondrogenic potential. In a porcine full-thickness cartilage defect model, Tissue bioink-printed constructs promoted robust cartilage regeneration, demonstrating enhanced ECM deposition, histological cartilage characteristics, and significantly improved biomechanical properties (p < 0.001) at six months. Furthermore, PKH-26-labeled pSMSCs persisted within the defect site, indicating sustained cellular viability and potential contribution to tissue remodeling. These findings suggest that DCECM-augmented mesenchymal condensation provides a biomimetic biofabrication strategy that enhances chondrogenesis without the need for post-printing growth factors and cross-linking steps, presenting a promising approach for a clinically translatable cartilage repair.