Investigation on bioactivity, biocompatibility, thermal behavior and antibacterial properties of calcium silicate glass coatings containing Ag

• Silver-containing calcium silicate glasses were synthesized via sol–gel.
• Dip coating allowed one to use synthesized materials to prepare antibacterial coatings.
• Coating antibacterial activity is directly proportional to Ag content.
• The coated titanium substrates showed higher bioactivity than the uncoated.
• The coated titanium substrates showed higher bioactivity than the uncoated.

The aim of this study has been the preparation of dental implants with potential antibacterial properties. Bioactive glasses containing different percentages of silver have been synthesized via the sol–gel method and used to coat titanium implants by means of a dip coating technique. The glasses obtained have the following general formula, 70S30CxA, which is related to its composition (in mol%): 70% of SiO2 (S), 30% of CaO (C) and x% of Ag2O (A), with 0.08 ≤ x ≤ 0.27. Fourier Transform Infrared (FTIR) spectroscopy and simultaneous thermogravimetry/differential thermal analysis (TG/DTA) were used to characterize the materials. Scanning electron microscopy (SEM) has been used to investigate the coating morphology. Moreover, the films obtained have been characterized in order to verify their antibacterial activities as well as their bioactivity and biocompatibility as a function of Ag content. SEM/EDX analysis has shown that the films are bioactive because they are able to stimulate the hydroxyapatite nucleation on their surface when soaked in a simulated body fluid (SBF). WST-8 assay on 3T3 cells seeded on coated titanium substrates has proved that the coatings don't induce cytotoxicity. However, the results have shown that both the bioactivity and biocompatibility of coatings decrease slightly at high Ag contents. In contrast, antibacterial activity of the films against the Staphylococcus aureus increases with an increase of the silver amount.