45S5 bioactive glass reactivity by dynamic vapour sorption

Abstract Reactivity in an aqueous medium is a key parameter for determining the potential bioactivity (i.e., the ability to form a bond to bone) of bioactive and soluble glasses. In this study, dynamic vapour sorption (DVS), a gravimetric technique that measures vapour sorption under controlled relative humidity (RH) and temperature, was used to investigate the short-term aqueous interactions of Bioglass® 45S5 (BG). Specifically, DVS was applied to monitor the sorption characteristics of BG particles of three different sizes exposed to variable RH between 0 and 90%. In addition, the effect of directly exposing these glasses to 90% RH for up to 24 h and its effect on the structural and morphological properties was analysed. Attributable to their larger surface areas, smaller BG particles adsorbed more vapour, and consequently underwent larger total and final mass percent changes as well as greater extent of surface transformation. Precise vapour sorption rates, determined using DVS, were correlated with BG particle surface area and initial rate of ion release when immersed in deionized water, thus demonstrating the ability of DVS to accurately predict reactivity and potential bioactivity.