The Synthesis Of Magnesium And Silver-doped Hydroxyapatite By Step Reaction And Its Biological Applications

The magnesium-doped hydroxyapatite (Mg-HA) and silver-dopedhydroxyapatite (Ag-HA) were synthesized by ion exchange process and glucosereduction based on the chemical co-precipitation method, respectively. Thetemperature of reaction was controlled at90°C, while the pH value was about8.5.The X-ray diffraction (XRD) analysis revealed that the lattice disorder increased withMg substitution in the Mg-HAs, and the peaks of silver could be clearly observed inthe pattern of Ag-HAs. Fourier transform infrared spectrometer (FTIR) demonstratedthe existence of hydroxy and phosphate groups in the materials. The size andmorphology of two metal-doped HA were investigated by scanning electronmicroscopy (SEM) and transmission electron microscopy (TEM). Results showed themorphology changes with different Ca/Mg or Ag/Ca feeding ratios. The chemicalcompositions of the materials were investigated by inductively coupled plasmaemission spectrometer (ICP). The (Ca+Mg)/P ratios of Mg-HAs were close to thestoichiometric Ca/P ratio in HA (1.67), while the Ca/P ratios of Ag-HAs were higherthan that of HA due to the loss of phosphate. In addition, the methyl-thiotetrazole(MTT) assay proved the Mg-HAs had low cell cytotoxicity. At the same time, theantibacterial properties of the Ag-HAs were investigated by the minimum bactericidaloncentration (MBC) method. Results demonstrated that the Ag-HAs had goodantibacterial properties on the streptococcus mutans, porphyromonas gingivalis andfusobacterium, and no obvious antibacterial activity was observed against candidaalbicans.