The preparation and cytocompatibility of injectable thermosensitive chitosan/poly(vinyl alcohol) hydrogel

In order to investigate the strength, structure and cell cytocompatibility of injectable thermosensitive chitosan (CS)/poly(vinyl alcohol) (PVA) composite hydrogel, chitosan hydrochloride solution was transferred to a neutral pH and mixed with different proportions of PVA, then the gelation time and strength of these different hydrogels were tested and spatial structures were observed under a scanning electron microscopy (SEM) after freeze-drying. The cytocompatibility of the hydrogels was evaluated through cytotoxicity test and three-dimensional culture with bone marrow mesenchymal stem cells. The results showed that the CS/PVA solution kept in liquid state at low temperature (0–4°C) and turned into transparent elastomer about 15–20 min at 37°C. Gelation time was prolonged, the strength increased and porous structure became dense with the PVA content increased in the mixed hydrogel. The cytotoxicity grades of these gels were from 0 to 1. Rabbit bone marrow mesenchymal stem cells could survive and proliferate in the gel within 3 weeks, and the gel had good cytocompatibility. It was concluded that thermosensitive CS/PVA composite hydrogel not only has interpenetrating network structure and better mechanical strength, but also has good cytocompatibility, and may be used as an injectable scaffold for tissue engineering.