Mechanochemical Synthesis of Largely Amorphous Silver‐Doped Calcium Phosphate Particles

ABSTRACT Planetary ball milling of β ‐tricalcium phosphate ( β ‐TCP) powders in acetone using 1 mm zirconia beads as milling media has been shown to produce largely amorphous, anhydrous calcium phosphate powders. This method enhances the release of Ca 2 ⁺ and phosphate ions from the resulting particles. In this study, silver ions were successfully and uniformly incorporated into the calcium phosphate matrix by adding just 1 wt% Ag 3 PO 4 during the mechanochemical process, allowing for the straightforward fabrication of particles with well‐dispersed Ag⁺ ions. When 5 wt% Ag 3 PO 4 was used, both dispersed Ag⁺ ions and metallic silver nanoparticles were detected. Upon immersion in HEPES buffer solution (pH 7.40), the concentrations of Ag⁺, Ca 2 ⁺, and phosphate ions increased significantly within 24 h. Powder x‐ray diffraction revealed time‐dependent changes during immersion, attributed to hydroxyapatite formation. Antibacterial testing showed that particles doped with 1 wt% Ag 3 PO 4 exhibited strong antibacterial activity against Escherichia coli and Staphylococcus aureus . This mechanochemical route offers a simple and effective method for uniformly incorporating trace levels of silver ions into anhydrous amorphous calcium phosphate particles.