Thermally stable bioactive borosilicate glasses: Composition–structure–property correlations

Processing of commercial bioactive glasses in the form of scaffolds, fibers and coatings on metal implants is a major challenge due to their high crystallization tendency leading to loss of many desirable functionalities relevant to bone tissue engineering applications. In this context, this work focuses on developing borosilicate bioactive glasses with improved thermal stability from the detailed understanding of composition–structure–property correlations. Structural studies through Raman and magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy revealed the formation of a highly crosslinked network rich in B–O–Si bonds facilitating enhanced thermal stability (> 150 °C) for 17.96–35.92 mol% B 2 O 3 containing glasses. These glasses also exhibit substantially improved in vitro biological properties such as biomineralization, cell proliferation, alkaline phosphatase (ALP) expression and antibacterial efficacy owing to predominance of B–O–Si and B–O–B bonds. However, more detailed data with pre-clinical studies are needed to confirm these observations, and for using them for specific applications. Graphical abstract