Antibacterial Effect and the Mechanism of Cu~(2+), Zn~(2+) Bearing Nano-hydroxyapatite

Nano-hydroxyapatite (n-HA) slurry was synthesized at normal pressure, and Cu-bearing nano-hydroxyapatite (Cu-HA), Zn-bearing nano-hydroxyapatite (Zn-HA) and (Cu, Zn)-bearing nano-hydroxyapatite (Cu-Zn-HA) were prepared by the ion exchange method in water medium. The properties of antibacterial materials were characterized by AAS, XRD and TEM. The results of XRD analysis indicate that Cu2+ and Zn2+ can occupy Ca2+ site and also enter the lattice of hydroxyapatite. The results of antibacterial experiments show that Cu-HA and Cu-Zn-HA have better antibacterial ability on E. coli and S. aureus, while the antibacterial effect of Zn-HA is not significant. From the analysis of the antibacterial results, it can be concluded that two mechanisms play the important role in the antibacterial ability, one is electrostatic attraction which making large amount of bacteria adhere on the n-HA surface, the other is the release of antibacterial metal ions slowly into medium which can inhibit and kill bacteria.