Hydroxyapatite Nanophases Augmented with Selenium and Manganese Ions for Bone Regeneration: Physiochemical, Microstructural and Biological Characterization

Hydroxyapatite (HAP) nanopowders with different manganese (Mn) and selenium (Se) contents with Mn/Ca and Se/P molar ratio of 1 mol%, 2.5 mol% and 5 mol% were synthesized by wet-co-chemical precipitation method. The results revealed that with either Mn or Se doping, ion-substituted apatite phase was achieved with good crystallographic features. The combined evidence obtained from spectrometric techniques revealed that nanocrystalline HAP was effectively doped with Mn and Se ions, where Se in form of SeO replaced PO and Mn replaced Ca. Mn and Se doped HAP samples exhibited rod-like and needle-like morphology with strong tendency to form agglomerates. HAP enriched with Mn and Se represented a strong antibacterial effect and also showed prominent blood compatibility. From the biocompatibility testing, it was evident that Mn and Se doped HAP augmented the osteoblasts adhesion, migration and proliferation in a dose-dependent manner. To conclude from this study, it is clearly evident that the doping amount of both Mn and Se ions can determine the size and morphology of the final HAP product. Therefore, Mn and Se HAP nanopowders with molar ratio less than 5 mol% without any heat treatment can provide good crystallographic features to HAP with satisfying micro-structural, thermal and biological properties.