Customizing the spatial distribution and release of silver for the antibacterial action via biomineralized self-assembling silver-loaded hydroxyapatite

Abstract

The fabrication of a rationally designed silver-loaded hydroxyapatite (Ag–HA) material to balance antibacterial activity, biological safety and chemical stability is a significant challenge. The key to solving this problem lies in controlling the release of Ag⁺ ions. This ambition has been skillfully fulfilled by a layer-by-layer self-assembly approach via Staphylococcus aureus (S. aureus)-templated mineralization. The abundant functional groups, namely teichoic acid and carboxyl groups, on S. aureus could induce the nucleation and growth of Ag–HA because of the strong chelating effect on the Ca²⁺ and Ag⁺ ions. The spatial distribution of silver in Ag–HA microspheres has been designed by modifying the sedimentary order of the Ag⁺ and Ca²⁺ ions. The as-prepared samples were characterized by XRD, SEM, EDS, TEM, XPS, FT-IR and Zate potential methods. The release of Ag⁺ ions was measured by atomic absorption spectrometry. The results indicate that the derived Ag–HA hybrid antibacterial materials do not only inherit the uniform size of the S. aureus template well but also exhibit customized spatial distribution and release of Ag⁺ ions.