The Effect of Zinc Doping on the Cytocompatibility and Antibacterial Efficacy of Hydroxyapatite Nanoparticles for Treatment of Bone Infection

In the face of antibiotic resistance, new antibacterial methods are urgently needed for bone infections. Local delivery of therapeutic metal ions via osteogenic nanoparticles (NPs) is a viable alternative, but high concentrations risk toxicity to mammalian cells. In this study first four ions (Mg2+, Sr2+, Cu2+, Zn2+) were assessed for cytocompatibility and antibacterial properties. Only zinc ions showed antibacterial effects at non-toxic levels. Subsequently, zinc-doped hydroxyapatite nanoparticles (ZnHA NPs) were synthesized with varying zinc content (0–20 mol%). ZnHA NPs were characterized on size, morphology, composition, and antibacterial activity, with 15 mol% ZnHA NPs exhibiting the optimal balance between cytocompatibility and antibacterial efficacy. These NPs show promise as deliverable biomaterials for bone infection treatment.