Impact of fluid flow rate on the dissolution behavior of bioactive glass S53P4

Bioactive glasses have proven to be effective grafting materials for the repair of bone tissue defects. However, accurately predicting the degradation behavior of bioactive glasses in vivo remains challenging. The present study examines the effect of flow rate on the dissolution behavior of bioactive glass S53P4 in plain Tris buffer and Tris-buffered simulated body fluid. Ion concentrations, pH changes, and alteration layer development at the glass surface were studied over 24 h for the three different flow rates studied. The study revealed significant flow rate dependent differences in the glass dissolution rate, ion release, and reaction layer development. At the lowest flow rate, 0.04 ml min −1 , highly incongruent dissolution and formation of diffusion-limiting reaction layers were identified. At the medium flow rate, 0.2 ml min −1 , the dissolution rate was sensitive to solution saturation state effects. At the highest flow rate, 0.6 ml min −1 , dissolution became more surface-controlled and was nearly congruent. The findings support the idea that bioactive glass dissolution can be described by a combination of diffusion barrier and chemical affinity concepts. In demonstrating the impact of flow rate on bioactive glass dissolution, the study underscores the importance of performing dynamic in addition to static dissolution tests.