Enhanced osteogenesis potential of MG-63 cells through sustained delivery of VEGF via liposomal hydrogel

Abstract

The challenges of using vascular endothelial growth factor (VEGF) to promote osteoblastic differentiation include short half-life and the narrow therapeutic window effects. A carrier system comprising a combination of chitosan hydrogel and liposomes may improve the therapeutic efficacy of VEGF for bone regeneration. Hence, this study aimed to investigate the effects of delivery of VEGF via liposomal hydrogel scaffold on the osteogenesis of MG-63 cell line. Liposomal hydrogel scaffold was fabricated and then characterized in terms of the morphological, physical and chemical properties using TEM, FESEM and FTIR. The MG-63 cell line was used as the osteoblastic in vitro model. In 2D analysis, MG-63 cells were cultured in osteogenic medium (OM) with complete medium serving as a control. In 2.5D analysis, the MG-63 cell line was cultured on liposomal hydrogel + VEGF as the test group. The osteogenic effects of VEGF were compared to the control groups i.e., hydrogel without liposomes + VEGF, OM supplemented with a bolus of VEGF, and OM without VEGF. Cell morphology, viability, differentiation and mineralization potential were investigated in both 2D and 2.5D analyses using inverted microscopy or FESEM, MTT assay, ALP activity, osteogenic gene expressions (COL1A1 and OCN) and Alizarin red staining. The characterisation of scaffold in this study has shown that there were no significant differences in the morphological, physical, and chemical properties between hydrogel with and without liposomes (p>0.05). The 2D cell characterisation showed that MG-63 cell morphology, viability, ALP activity, osteogenic gene expression and mineralisation were significantly enhanced in the presence of OM (p<0.05). The final 2.5D culture demonstrated that the liposomal hydrogel + VEGF group enhanced cell proliferation, differentiation and mineralization of MG-63 cells, the effects of which were significantly greater compared to the control groups (p<0.05). In conclusion, liposomal hydrogel potentially enhanced the osteogenesis of MG-63 osteoblast-like cells by serving as a promising vehicle to deliver VEGF in a sustained manner.