Fine analysis of interaction mechanism of bioactive glass surface after soaking in SBF solution: AFM and ICP-OES investigations

Bioactive glasses have the physical characteristics enabling them to be used in bone tissue engineering applications. However, the exact mechanism of the interactions between the glass surface and environment leading to the transition from the vitreous phase to the crystalline phase remains a subject of study. This work focuses on the growth of a calcium phosphate layer on the surface of the glass after immersion in a mineral solution, which mimics the mineral phase of human blood. The investigations use the Inductively Coupled Plasma and the Atomic Force Microscopy to establish the kinetic of crystallization, the kinetic of chemical reactivity and the surface transformations such as structure, texture and morphology of the bioactive glass. Obtained results show the progressive formation of a hydroxyapatite layer within 2 weeks. This crystal which is that of the bone belongs to the crystallographic structure within space group of P6(3/m) In addition, results show a decrease of the gradient of thickness which varies according to the immersion time from 7.5 mu m to 2.8 mu m and an increase of the homogeneity of the surface visible by the lowering of the gradient in the phase measurement from 60 angstrom to 15 angstrom.