Investigating the effect of TiO₂ on the structure and biocompatibility of bioactive glass

Titanium (Ti⁴⁺ ) containing materials have been widely used in medical applications due to its associated bioactivity in vivo. This study investigates the replacement of Si⁴⁺ with Ti⁴⁺ within the system SiO₂ -Na₂ O-CaO-P₂ O₅ to determine its influence on glass structure. This strategy was conducted in order to control the glass solubility to further improve the cellular response. Ti⁴⁺ incorporation was found to have little influence on the glass transition temperature (T_g  = 520 ± 8°C) and magic angle spinning-nuclear magnetic resonance (MAS-NMR) shifts (-80 ppm) up to additions of 18 wt %. However, at 30 wt % the T_g increased to 600°C and MAS-NMR spectra shifted to -88 ppm. There was also an associated reduction in glass solubility as a function of Ti⁴⁺ incorporation as determined by inductively coupled plasma optical emission spectroscopy where Si⁴⁺ (1649-44 mg/L) and Na⁺ (892-36 mg/L) levels greatly reduced while Ca²⁺ (3-5 mg/L) and PO43- (2-7 mg/L) levels remained relatively unchanged. MC3T3 osteoblasts were used for cell culture testing and it was determined that the Ti⁴⁺ glasses increased cell viability and also facilitated greater osteoblast adhesion and proliferation to the glass surface compared to the control glass. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1703-1712, 2016.