3D bio-printed proteinaceous bioactive scaffold loaded with dual growth factor enhanced chondrogenesis and in situ cartilage regeneration

Articular cartilage has a limited self-healing capacity, leading to joint degeneration and osteoarthritis over time. Therefore, bioactive scaffolds are gaining attention as a promising approach to regenerating and repairing damaged articular cartilage through tissue engineering. In this study, we reported on a novel 3D bio-printed proteinaceous bioactive scaffolds combined with natural porcine cancellous bone dECM, tempo-oxidized cellulose nanofiber (TOCN), and alginate carriers for TGF-β1, FGF-18, and ADSCs to repair cartilage defects. The characterization results demonstrate that the 3D scaffolds are physically stable and facilitate a controlled dual release of TGF-β1 and FGF-18. Moreover, the key biological proteins within the bioactive scaffold actively interact with the biological systems to create a favorable microenvironment for cartilage regeneration. Importantly, the <i>in vitro</i>, <i>in vivo</i>, and in silico simulation showed that the scaffolds promote stem cell recruitment, migration, proliferation, and ECM deposition, and synergistic effects of TGF-β1/FGF-18 with the bioactive scaffolds significantly regulate stem cell chondrogenesis by activating the PI3K/AKT and TGFβ1/Smad4 signaling pathways. After implantation, the proteinaceous bioactive scaffold led to the regeneration of mechanically robust, full-thickness cartilage tissue that closely resembles native cartilage. Thus, these findings may provide a promising approach for regulating stem cell chondrogenesis and treating in situ cartilage regeneration.