Antibacterial and physical characteristics of silver-loaded hydroxyapatite/alginate composites

The influence of silver ions on the antibacterial properties and morphology of hydroxyapatite-silver (HA-Ag) and hydroxyapatite-alginate-silver (HA-Alg-Ag) nanocomposites was studied. The microstructure and phase composition of the obtained nanocomposites were investigated by scanning electron microscopy, transmission electron microscopy, x-ray diffraction and Fourier transform infrared spectroscopy, and the formation of the crystalline phase of Ag3PO4 was proved. According to the results, silver ions were incorporated into the HA structure, partially replacing calcium ions. Assessment of the antimicrobial activity was carried out on Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacterial test cultures by the co-incubation and modified agar diffusion methods. We demonstrated that the antimicrobial and adhesive properties of both Ag-HA and HA-Alg-Ag are strongly affected by the crystal lattice structure, controlled by the location of silver ions. The composite materials could be of great interest in the biomedical field, including in the design of coatings that prevent or slow the development of bacterial biofilms.