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 degrees C) and turned into transparent elastomer about 15-20 min at 37 degrees 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.