Multi-layer bactericidal silver - calcium phosphate coatings obtained by RF magnetron sputtering

Currently, antibiotic prophylaxis is not sufficient for the treatment of infections associated with implantable materials. For this reason, it is necessary to develop new alternatives, complementary to traditional pharmaceutical methods, in order to treat these infections. This study aims to respond to this need. In it, multi-layer bactericidal silver - calcium phosphate coatings were obtained on Ti-6Al-4V by radio frequency magnetron sputtering. A 4.2 Ag atomic % and Ca/P ratio of 2.15 were measured by energy dispersive X-ray spectroscopy. The structural and phase analysis, performed respectively by micro-Raman spectroscopy and X-ray diffraction, allowed characteristic vibration bands of the CaP and hydroxyl groups, as well as hydroxyapatite peaks, to be appreciated. Additionally, the surface topography was studied by atomic force microscopy, revealing granular morphology with grain size of 191 +/- 32 nm and a root mean square of 21.1 nm. Additionally, a water contact angle of 77.8 degrees was registered using a goniometer. The bactericidal effect of the coatings at relatively low Ag concentration (< 0.01 mg/L) was observed through an inhibitory halo generation in the culture of the Staphylococcus aureus and Pseudomonas aerugirtosa strains. Meanwhile, the non-toxic character, proliferation and adhesion of Saos-2 osteoblast to the coating surface were determined by means of MIT assays, fluorescence and scanning electron microscopy visualization.