Mineral-substituted hydroxyapatite reinforced poly(raffinose-citric acid)–polyethylene glycol nanocomposite enhances osteogenic differentiation and induces ectopic bone formation

Abstract

In this study, mineral-substituted hydroxyapatite (M-HA (5, 10, and 15 wt%)) reinforced poly(raffinose-citric acid)–polyethylene glycol–poly(raffinose-citric acid) (PRC–PEG–PRC) was synthesized employing a microwave irradiation technique. The ability of the fabricated nanocomposite for bone development was studied in vitro using human osteosarcoma HOS MG63 cells and in vivo after subcutaneous implantation into Wistar rats. This porous M-HA/PRC–PEG–PRC nanocomposite encouraged the adhesion, growth, and multiplication of HOS cells, as displayed by their uniform morphology and as determined by cell adhesion and the live/dead cell assay. Upon osteogenic differentiation, superior ALP activity and bone-related gene expression were observed for the HOS cells on the M-HA/PRC–PEG–PRC nanocomposite compared with the cells on pure PRC–PEG–PRC scaffolds. In in vivo implantation experiments, ossification and development of trabeculae were detected on the M-HA (15 wt%)/PRC–PEG–PRC nanocomposite in contrast to pure PRC–PEG–PRC. In addition, the porous M-HA (15 wt%)/PRC–PEG–PRC nanocomposite demonstrated the capacity for ectopic bone arrangement. Moreover, decreased numbers of bacterial colonies of Staphylococcus aureus and Escherichia coli were observed in the presence of the M-HA/PRC–PEG–PRC scaffolds, indicating the reduced risk for implant failure after implantation. The good cell affinity of the M-HA/PRC–PEG–PRC porous materials indicated that they might be used as scaffolds for bone tissue engineering.