Effect of carboxylated graphene nanoplatelets on mechanical and in-vitro biological properties of polyvinyl alcohol nanocomposite scaffolds for bone tissue engineering

Owing to the drastically increasing occurrence of bone disorders, it is essential to develop synthetic materials suitable for bone tissue regeneration. In the present study, biocomposite scaffolds of polyvinyl alcohol (PVA) reinforced with different concentrations of functionalized graphene nanoplatelets (GNP: 0, 0.5, 1 and 1.5 wt%) were prepared using freeze drying method. The prepared scaffolds were characterized for their physicochemical, mechanical and in-vitro biological properties. To study the effect of GNP reinforcement on the MG-63 osteoblast cells behavior scanning electron microscopy (SEM), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, alkaline phosphatase (ALP) activity assay and alizarin red stain-based (ARS) assay were performed. The homogenous dispersion of GNP up to 1 wt% improved the mechanical and biological properties of the nanocomposite scaffolds. The tensile strength of the scaffolds with 1 wt% of GNP was found to be 16.48 +/- 0.50 MPa which is 20.68 times more than the PVA sample. The low concentration of GNP (1 wt%) provided the most favorable microenvironment for osteoblast cell proliferation and differentiation. Further increase in GNP concentration (1.5 wt%) lead to agglomeration of GNP which deteriorates the properties of nanocomposite. The study showed that the relatively low concentration of GNP in PVA-GNP scaffolds certainly exhibit a beneficial effect on the mechanical and biological properties of nanocomposite scaffolds, thus proving to be a promising biomaterials for bone tissue engineering applications.