Gallium-containing phosphosilicate glasses: Functionalization and in-vitro bioactivity

A gallium containing glass 45.7SiO₂·24.1Na₂O·26.6CaO·2.6P₂O₅·1.0Ga₂O₃ (referred to as “Ga1.0”) and a parent Ga-free glass 46.2SiO₂·24.3Na₂O·26.9CaO·2.6P₂O₅ (hereinafter represented as “H”), corresponding to Bioglass® 45S5, were functionalized with Tetraethoxysilane (TEOS) and (3-Aminopropyl)triethoxysilane (APTS) in order to improve their ability to bond with biomolecules, such as drugs, proteins, and peptides. Functionalization with TEOS and APTS promoted the increment in OH groups and formation of NH₂ groups on the glass surface, respectively. The presence of OH or NH₂ groups was investigated by means of IR spectroscopy and elemental analysis. Moreover, in vitro study of these functionalized glasses was performed in simulated body fluid (SBF) so as to investigate the effect of functionalization on the bioactive behavior of H and Ga1.0. The results showed that the functionalization was obtained along with maintaining their bioactivity. The surfaces of both functionalized glasses were covered by a layer of apatite within 30 days of SBF immersion. In addition, CaCO₃ was also identified on the surface of APTS functionalized glasses. However, no gallium release was detected during SBF soaking.