Structure, dissolution behavior, cytocompatibility, and antibacterial activity of silver-containing calcium phosphate invert glasses.

Abstract

Novel CaO-P₂ O₅ -Nb₂ O₅ -Ag₂ O invert glasses with substitution Ag₂ O for Nb₂ O₅ were successfully prepared using a melt-quenching method. Ag₂ O in the glasses act as a network modifier oxide, playing the same role as Na₂ O, which breaks the phosphate chains. Analysis of the ultraviolet-visible absorption spectra of the glasses showed that the glass matrix contained ionic silver species and silver nanoparticles. Approximately 0.05 mM of Nb⁵⁺ ions released from the glasses, which would be expected to stimulate osteoblast differentiation. A glass containing 1 mol % Ag₂ O showed a linear increase in the releasing amount of Ag⁺ ions with increasing soaking time, whereas glasses containing 3-5 mol % Ag₂ O showed Ag⁺ ion concentrations of around 13 μM at day 3, and then maintained similar values until day 7. When the solution was replaced with fresh solution every 2 days, the Ag⁺ ion dissolution amounts indicated almost constantly 13 μM due to AgCl formation. There were no differences in the numbers of primary osteoblast cells on silver-free and silver-containing glasses after cultivation for 1-7 days. The silver-containing calcium phosphate invert glasses showed cytocompatibility with simultaneous antibacterial activity to Escherichia coli and Staphylococcus aureus. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3127-3135, 2017.