Nanoparticles of cobalt-substituted hydroxyapatite in regeneration of mandibular osteoporotic bones

Abstract

Indications exist that paramagnetic calcium phosphates may be able to promote regeneration of bone faster than their regular, diamagnetic counterparts. In this study, analyzed was the influence of paramagnetic cobalt-substituted hydroxyapatite nanoparticles on osteoporotic alveolar bone regeneration in rats. Simultaneously, biocompatibility of the material was tested in vitro, on osteoblastic MC3T3-E1 and epithelial Caco-2 cells in culture. The material was shown to be biocompatible and nontoxic when added to epithelial monolayers in vitro, while it caused a substantial decrease in the cell viability as well as deformation of the cytoskeleton and cell morphology when incubated with the osteoblastic cells. In the course of six months after the implantation of the material containing different amounts of cobalt, ranging from 5 – 12 wt%, in the osteoporotic alveolar bone of the lower jaw, the following parameters were investigated: histopathological parameters, alkaline phosphatase and alveolar bone density. The best result in terms of osteoporotic bone tissue regeneration was observed for hydroxyapatite nanoparticles with the largest content of cobalt ions. The histological analysis showed a high level of reparatory ability of the nanoparticulate material implanted in the bone defect, paralleled by a corresponding increase in the alveolar bone density. The combined effect of growth factors from autologous plasma admixed to cobalt-substituted hydroxyapatite was furthermore shown to have a crucial effect on the augmented osteoporotic bone regeneration upon the implantation of the biomaterial investigated in this study.

Cationic and Anionic Substitutions in Hydroxyapatite

“…Cobalt-substituted hydroxyapatites (Co-HAps) have been synthesized by the hydrothermal method, obtaining hydroxyapatites containing 5-15 wt% of Co 2+ [296], and by wet method, obtaining powders with a Co 2+ content between 0.46 wt% and 3.79 wt% [297].…”

Chitosan-PLGA polymer blends as coatings for hydroxyapatite nanoparticles and their effect on antimicrobial properties, osteoconductivity and regeneration of osseous tissues

“…As for doping HAp, each of its three constitutive ions — calcium, phosphate and hydroxyl — can be substituted with other ions and dozens of chemically different forms of HAp are known so far [14]. Hydrothermal synthesis has been used in our lab to create nanostructured HAp in which calcium ions were substituted with cobalt, and the resulting material exhibited good biological properties during in vivo testing [15]. Other ionic substitutions, including predominantly Mg, Zn, Si, Sr, Fe, Co and carbonate, alongside rarer dopants, e.g.…”

The role of hydroxyl channel in defining selected physicochemical peculiarities exhibited by hydroxyapatite

“…Then, a metacarpal fracture in goats healed much faster in the presence of static magnetic field stimulation (800 G/cm 2 ) and the healing process was paralleled by an increase in preferential alignment and crystallinity of HAp crystals in bone 69 . Cobalt-doped HAp also facilitated the regeneration of mandibular osteoporotic bones in rats 70 . Even outside the biomedical context, the effects of external fields on the habit of crystal growth of HAp have been observed.…”