Extracellular-matrix cryogels for cartilage tissue engineering

Abstract

In this thesis, we investigated highly porous extracellular matrix (ECM) cryogels for cartilage tissue engineering. For ECM cryogel fabrication, methacrylated chondroitin sulfate (MeCS) or methacrylated hyaluronic acid (MeHA) was co-polymerized with PEG-based or gelatin-based system via free radial initiation under freezing condition. This procedure induced ice crystal formation resulting in macroporous structures within ECM-cryogels. The developed PEG-based ECM-cryogel system exhibited average macroporosity of 75% and supported the chondrocyte infiltration. Additionally, gelatin-based ECM cryogel showed average porosity of 65%. When rabbit chondrocytes were cultured on PEG-based ECM cryogels, PEG/CS cryogels stimulated aggrecan gene expression and GAG accumulation, whereas PEG/HA cryogels stimulated type II collagen gene expression and collagen accumulation. Presence of CS in gelatin-based cryogels showed strong upregulation in all types of cartilage related genes (type II collagen, type X collagen, aggrecan, HAS2, PRG4, Link protein). Gelatin/HA cryogel showed significant increase in HAS2, link protein and type II collagen. These results demonstrated that the ECM cryogels can be utilized to promote specific ECM secretion for cartilage tissue engineering