Structural Characterization of Silver Containing Hydroxyapatite Synthesized by Solid Phase Reaction

Abstract

Silver containing hydroxyapatite (AgHA) was fabricated by the heat treatment at various temperatures. AgHA composite powders were prepared by ball-milling with crystalline hydroxyapatite powder and silver oxide. These structural characterizations were carried out by SEM, XRD, FT-IR, and XANES measurements. In the case of AgHA sintered at 800 °C, XRD results showed that the peaks of metallic silver and other silver compounds disappeared, and the a-axis of hydroxyapatite expanded drastically. Furthermore, SEM images shows that silver particles were not observed for AgHA sintered at 800 °C and reappeared for AgHA sintered at 1000 °C. The XANES spectrum of Ag-L₃ edge of AgHA sintered at 800 °C was different from ones of reference materials. According to IR measurements, it seemed that the substitution behavior of silver ion was affected by carbonate ions in hydroxyapatite structure through the heat treatments. Consequently, calcium ions were thought to be substituted by silver ions for AgHA sintered at 800 °C. In addition, antibacterial tests showed that AgHA sintered 800 °C and 1000 °C possessed high antibacterial properties against MRSA.