Abstract
We had developed a biomimetic scaffold comprising chondroitin-6-sulfate/dermatan sulfate/chitosan (CSC/DS/chitosan) for culturing chondrocytes and enhancing the engineered cartilage formation. However, the mechanical properties of freeze-dried CSC/DS/chitosan scaffold is not suitable for the repair of full-thickness defects in load-bearing site。 Therefore, we prepared macroporous CS/chitosan/gelatin cryogel scaffolds with elasticity via cryogelation process for cartilage tissue engineering. We synthesized four scaffolds with either no CS (control) or different CS contents and analyzed their physiochemical properties. The CS/chitosan/gelatin cryogels contained large, interconnected pores and allowed for uniform seeding of adipose-derived stem cells (ASCs), as confirmed by scanning electron microscopy (SEM). LIVE/DEAD staining showed that the cryogels are noncytotoxic and cell cluster formation was observed. The incorporation of CS can up-regulate chondrospecific gene expression. The optimal formulation comprised of 0.3 mg CS per chitosan-gelatin scaffold for its better cell attachment and chondrogenic effect. We further use the scaffolds for the culture of baculovirus-engineered ASCs. Results showed that with sustained baculovirus-mediated BMP-6/TGF-3 stimulation, the cell attachment and proliferation rate of ASCs decrease and no obvious cartilage extracellular matrix (ECM) accumulation. Engineered cartilage that resembles native cartilage will form by modification of crosslinking process and optimization of virus dosage.