Boron and Zinc Co-doped Hydroxyapatites for Bone Tissue Engineering Applications

In this study, effects of B and Zn co-doping on structural and biological properties of hydroxyapatite (HA) were investigated. Effect of co-doping on synthesized HA groups was characterized by SEM, ICP-OES, XRD, FTIR, and dynamic light scattering. It was revealed that 8 mol% B led to a decrease in particle size, whereas increasing Zn resulted in increasing mean particle size. FTIR spectra verified presence of PO₄^3- and BO₃^3- in the HA structure. XRD analysis revealed that both B and Zn decreased HA phase percentage, crystallinity and crystallite size. Bioactivity of the HA groups increased with presence of B and Zn. Dual effect of B and Zn on viability and proliferation of human adipose derived stem cells (hADSCs) was also investigated. It was found that 8 mol% B doped and all B & Zn-doped HA groups increased cell viability and proliferation, except 8 mol% B & 8 mol% Zn doped HA. Moreover, 0.5 mg/ml 8 mol% B & 4 mol% Zn doped HA group significantly increased 14-day ALP activity of hADSCs and vessel area of human umbilical vein endothelial cells (HUVECs). Overall, Co-doping of B (8 mol%) and Zn (4 mol%) to HA provided both proliferative and osteogenic effects on hADSCs and angiogenic effect on HUVECs. Our findings suggest that B and Zn co-doped HA holds promise for bone tissue engineering applications.