The effect of hybridization of hydrogels and poly(L-lactide-co-ε- caprolactone) scaffolds on cartilage tissue engineering

For repairing cartilage defects by cartilage tissue engineering, it is important that engineered cartilage that is fabricated with scaffolds and cells can maintain the biological and physiological functions of cartilage, and also can induce three-dimensional spatial organization of chondrocytes. In this sense, hydrogels such as fibrin gels (FG) and hyaluronan (HA) are widely used for application in cartilage treatment. However, the use of hydrogels alone as a scaffold has a physical weakness; the mechanical properties of hydrogels are too weak to endure complex loading in the body. In this study, for mimicking a native cartilage microenvironment, we made cell-hybrid scaffold constructs with poly(L-lactide-co-ε-caprolactone) (PLCL) scaffolds and hydrogels to guide three-dimensional spatial organization of cells and extracellular matrix. A highly elastic scaffold was fabricated from PLCL with 85% porosity and 300-500 μm pore size using a gel-pressing method. The mixture of rabbit chondrocytes and hydrogels was seeded on PLCL scaffolds, and was subcutaneously implanted into nude mice for up to eight weeks. The cell seeding efficiency of the hybrid scaffolds with FG or HA was higher than that of the PLCL scaffolds. From in vivo studies, the accumulation of cartilaginous extracellular matrices of constructs, which was increased by hybridization of hydrogels and PLCL scaffolds, showed that the cell-hybrid scaffold constructs formed mature and well-developed cartilaginous tissue. In conclusion, the hybridization of hydrogels and PLCL scaffold for three-dimensional spatial organization of cells would provide a biomimetic environment where cartilage tissue growth is enhanced and facilitated. It can enhance the production of cartilaginous extracellular matrices and, consequently, improve the quality of the cartilaginous tissue formed.