Self-healing nanocomposite hydrogels based on chitosan/ modified polyethylene glycol/graphene

The aim of this research is to prepare self-healing injectable nanocomposite hydrogels based on benzaldehyde-modified polyethylene glycol and chitosan, reinforced with graphene oxide (GO) for the delivery of pomegranate extract (PG) for hard tissue engineering. For this purpose, polyethylene glycol (PEG) was first modified by an aldehyde agent and mixed with chitosan to form hydrogels based on reversible Schiff-Base linkages. Nanocomposites were prepared with the addition of 0.5, 1.0, 1.5, and 2.0 wt% GO to the hydrogels. Then, PG was loaded into the final nanocomposite hydrogels as the drug model to promote cell proliferation and chondrogenesis. The scanning electron microscopy (SEM) images indicated that the incorporation of GO into the hydrogels increased the average pore size from 261 to 403 µm, resulting in a favorable porous structure. The results also showed an enhancement in the elastic properties as well as the compressive strength of the nanocomposite hydrogels with increasing GO content. The drug release profile followed a power-law kinetics, in which, the content of PG and GO affected the release rate. According to self-healing and injection tests, all the hydrogels had good injection and self-healing capabilities. The incorporation of GO into the hydrogel increased antibacterial properties to more than 99%. The in vitro assay indicated that PG loading provided a suitable environment for the growth and survival of cells on the hydrogels. Therefore, the designed system is a promising framework for the local delivery of pharmaceuticals for hard tissue engineering.