Functionalized temperature-sensitive copolymer for tissue engineering of articular cartilage and meniscus

Thermo-sensitive chitosan-g-poly(N-isopropylacrylamide) (CPN) and hyaluronic acid-g-CPN (HA–CPN) copolymer were fabricated by forming amide bond linkages between carboxyl-ended poly(N-isopropylacrylamide), chitosan, and HA. Aqueous polymer solutions showed reversibly soluble–insoluble phase transition characteristics, which is free-flowing at room temperature and turns into a rigid gel structure at 37 °C. SEM observation demonstrated an inter-connected microporous structure with pore-size ranging from 20 to 50 μm. Chondrocytes and meniscus cells attached and proliferated well when cultured on the copolymer hydrogel. The cells maintained high viability and showed distinct morphology. The aggregated chondrocytes on the thermo-reversible hydrogel surface can be easily detached and recovered by simply lowering the temperature.