Bacterial inhibition by chitosan coatings loaded with silver-decorated calcium phosphate microspheres

• Silver nanoparticles were attached to calcium phosphate microspheres.
• Silver-loaded microspheres were loaded into chitosan coating bound to titanium.
• Coatings on titanium inhibit bacterial biofilm.
• Increasing silver content on microspheres increased antimicrobial effect.

Porous calcium phosphate microspheres have been modified to contain nanoparticles of silver to provide both osteoconductive and antimicrobial components to implant coatings. These microspheres have been mixed with chitosan and bonded to titanium via alkyloxysilane reaction. Silver concentration on calcium phosphate microspheres was varied from 0 to 50% and microspheres were loaded at 30 wt.% within chitosan coatings. Increasing concentrations of silver loaded on calcium phosphate microspheres within the chemically bound coating reduces bacterial viability by up to 90% in both anaerobic and aerobic pathogenic microorganisms, including Staphylococcus aureus, Prevotella denticola, and Porphyromonas gingivalis. This novel coating could reduce the incidence of infection in orthopaedic and dental implant applications.