An in-vitro bioactive, structural and degradation studies on B2O3–SiO2–P2O5–Na2O–CaO glass system incorporated with chromium ions

Abstract

Calcium borosilicate glasses with composition 43B2O3–5SiO2–2 P2O5–20 Na2O–(30–x) CaO–x Cr2O3 with 0 ≤ x ≤ 1 mol%, have been prepared by the conventional melt-quenching technique. The samples were characterized by FTIR, UV-vis-absorption and X-ray diffraction techniques. The physico chemical properties such as density, molar volume, oxygen packing density and chromium ion concentration were also evaluated. The data obtained indicated that the Cr2O3 will break the bonds of the glass network by the creation of non bridging oxygens (NBO’s); as a result an increase in the volume of the glass network due to loosely packed structure. Results from FTIR, UV-vis.-spectroscopy studies indicated that Cr2O3 acted as a network modifier, by converting four coordinated to three coordinated boron atoms. In this context, we have examined the bioactivity of various concentrations of Cr2O3 doped glasses with the help of simulated body fluid (SBF). After immersion of glasses in the SBF, formation of hydroxyapatite layer on the surface was confirmed by XRD, FT-IR and SEM-EDS analysis. The solubility test data indicated that a clear increase of degradability of glass and significant change in the pH of the body fluid was observed with the addition of chromium. The results showed that partial substitution of Cr2O3 with CaO positively influenced the bioactivity. Thus bioactivity is increased with increase in the content of Cr2O3.