A novel tantalum-containing bioglass. Part Ⅰ. Structure and solubility

摘要

Bioglasses are employed for surgical augmentation in a range of hard tissue applications. Tantalum is a bioactive and biocompatible transition metal that has been used as an orthopedic medical device. It has a range of biological and physical properties that make its incorporation into ionic form into bioactive glass systems promising for various clinical applications. The work herein reports the characterization and properties of novel tantalum-containing glasses. A series of glasses based on the system 48SiO_2-(36-X)ZnO-6CaO-8SrO-2P_2O_5-XTa_2O_5 with × varying from 0 mol% (TAO) to 0.5 mol% (TA2) were synthesized. The addition of small amounts of Ta_2O_5 did not cause crystallization of the glasses but increasing Ta_2O_5 content at the expense of ZnO was found to result in an increased number of bridging oxygens (BOs). This, along with the data recorded by differential thermal analysis (DTA) and magic angle spinning-nuclear magnetic resonance (MAS-NMR), confirms that Ta acts as a glass former in this series. Solubility experiments showed that minor changes in the glass structure caused by Ta incorporation (0.5 mol%) exhibited greater cumulative % weight loss, pH values and cumulative Zn~(2+) and Sr~(2+) ion concentration over a period of 30 days of maturation, when compared to Ta_2O_5-free glasses. The results presented in this article confirm that replacing ZnO with Ta_2O_5 in silicate glasses results in the formation of stronger bonds within the glass network without any adverse effects on the solubility of the glasses prepared from them.