Phosphate-based Glasses Prepared via Sol–Gel and Coacervation

Abstract

Phosphate-based glasses are a very promising class of multifunctional biomaterials. Being bioresorbable, they are capable of inducing simultaneous regeneration of tissue and delivery of drugs/therapeutic molecules and ions. Therefore, they can be used both as temporary implants and as controlled local delivery systems. Biomaterial-related infections, often causing revision surgery, could be prevented by incorporating into the biomaterial device antimicrobial agents that will be slowly released as the implant degrades. To date, the conventional technique used to prepare phosphate-based glasses is the melt-quenching process, which requires the melting of oxide powders at high temperatures (1000–1200 °C) followed by rapid cooling. However, this method often leads to non-homogeneous, bulk glasses that cannot be used for hosting temperature-sensitive molecules and can lead to reduction of antibacterial ions. Composition is also difficult to control because of the loss of volatile phosphate species during heating. This chapter describes two in-solution techniques for the synthesis of phosphate-based glasses alternative to the melt-quenching one: sol–gel and coacervation. A review of the literature published so far on the topics and a summary of key results is presented.