Preparation and structure of titanium-containing pyrophosphate glasses prepared using the liquid-phase method

Abstract

Phosphate invert glasses (PIGs) exhibit excellent biocompatibility because of their high chemical durability and controlled ion releasability. PIGs are composed of short phosphate units such as ortho- and pyrophosphate. This structure makes it difficult to obtain clear glass using the melt-quenching method. Our previous work reported that intermediate oxides (such as TiO₂ and Nb₂O₅)-containing PIGs exhibit good glass-forming ability and ion dissolution controllability. This work used a liquid-phase method to prepare PIGs at room temperature and pressure. Furthermore, TiO₂ was used to control ion releasability for biomedical applications. Titanium-containing PIGs were successfully prepared using a liquid-phase method. Pyrophosphate and titania formed P-O-Ti bonds with an increasing TiO₂ content in the glass, forming chain-like structural units such as (-O-P-O-P-O-Ti-O-)_n. The number of chain-like structures increased with an increasing TiO₂ content in the glass, improving the chemical durability. Hence, the ion releasability of titanium-containing PIGs prepared using the liquid-phase method can be controlled by the glass structure. Additionally, the PIGs exhibited good cell viability. Therefore, the PIGs are candidates for carriers of therapeutic inorganic ions for biomedical applications.