Structure, drug absorption, bioactive and antibacterial properties of sol-gel SiO2/ZrO2 materials

Zirconia widely used in biomedical applications has three crystalline forms, but the transformation from tet- ragonal to monoclinic is a serious problem in the biomedical field. In this regards, silica was added to stabilize the tetragonal zirconia phase. In fact, in this study four SiO 2 /ZrO 2 composites with different percentages of zirconia were synthesized with the sol-gel method. The aim of the present study was to check the suitability of these materials as a vector in the adsorption of an active drug. After the sintering process at different tem- peratures the materials have been chemically and biologically characterized. The interactions between the in- organic matrices and the identification of the different crystalline phases depending on the temperature of the thermal treatment were evaluated by Fourier transform infrared (FTIR) spectroscopy and XRD analysis. Furthermore, the absorption of ampicillin was carried out using UV–Vis. The bioactivity was studied after soaking the materials in simulated body fluid (SBF) for 21 days, by observing the characteristic peaks of hy- droxyapatite by FTIR analysis. Finally, after drug absorption the materials were incubated against Escherichia coli in order to evaluate the antibacterial properties and the release of the drug from the different composites.