Thermosensitive chitosan–Pluronic hydrogel as an injectable cell delivery carrier for cartilage regeneration

Injectable hydrogels have been studied for potential applications for articular cartilage regeneration. In this study, a thermosensitive chitosan–Pluronic (CP) hydrogel was designed as an injectable cell delivery carrier for cartilage regeneration. The CP conjugate was synthesized by grafting Pluronic onto chitosan using EDC/NHS chemistry. The sol–gel phase transition and mechanical properties of the CP hydrogel were examined by rheological experiments. The CP solution underwent a sol–gel transition around 25 °C at which the storage modulus (G′) approaches 104 Pa, highlighting the potential of this material as an injectable scaffold for cartilage regeneration. The CP hydrogel was formed rapidly by increasing the temperature. The morphology of the dried CP hydrogel was observed by scanning electron microscopy. In vitro cell culture was performed using bovine chondrocytes. The proliferation of bovine chondrocytes and the amount of synthesized glycosaminoglycan increased for 28 days. These results suggested that the CP hydrogel has potential as an injectable cell delivery carrier for cartilage regeneration and could serve as a new biomaterial for tissue engineering.