Synthesis and investigation of physico-chemical, antibacterial, biomymetic properties of silver and zinc containing hydroxyapatite

In the work we carried out microwave synthesis of modified hydroxyapatites (HA) with different content of ions. A solid solution based on HA remains a single-phase sample when the calcium ions are substituted by silver and zinc ions up to 5 % by weight (0.5 mole fraction). The microstructure parameters, morphology and the particle powders size were studied by X-ray diffraction analysis, IR spectroscopy, and scanning electron microscopy (SEM). It is shown that the modification of НA by silver (AgHA) and zinc (ZnHA) ions increases the size of its particles, the degree of crystallinity, and the pore sizes of the samples while reducing their specific surface and uniformity of their forms. Elemental analysis and distribution of elements over the surface of HA, AgHA, and ZnHA powders were performed by X-ray spectral microanalysis (RSMA). The ratio of Ca/P is within the range of 1.66-1.77 and corresponds to the ratio of Ca/P in stoichiometric HA and the HA entering bone tissue. The ability of AgHA- and ZnHA-substrates to form on their surface a calcium-phosphate layer from the simulated body fluid (SBF) at 37 °C is determined. This ability decreases in the order: in ZnHА it is less than in AgHА, but greater than in HА. The antibacterial activity of the samples was analyzed. The AgHA sample has both bactericidal and persistent bacteriostatic properties in the case of direct contact with Escherichia coli cells