Hydroxyapatites substituées nanocristallisées et leurs interfaces avec les milieux biologiques – NANOSHAP

This research project is focused on the fundamental study of biological apatites and their growth on biological interfaces. The main objective is to try to answer the following question "why and how mineralization occurs at the HAp/biological media interface'" The consortium, with complementary expertise, has been precisely chosen to fulfill this objective. The partnership is composed of inorganic materials chemists with expertise both in synthesis and characterization, physicists with expertise in advanced characterization techniques using large-scale facilities, biologists all in close interactions with physicians. Three systems will be studied based on research topics already developed within the constitutive teams of the consortium. They represent various examples of how nanocrystalline substituted apatites can develop in contact in biological media. Collagen-apatite nanocomposites. This topic is related to synthetic matrices, acting as realistic models for bone mineralization. Starting from a recent patent of our consortium, original compositions (including dense and ordered collagen matrices and hydroxyapatites nanocrystals) will be developed. Apatite layers on bioglasses. Also based on a recent patent of our consortium, the role of traces and proteins will be deeply studied, as very little is known about the fine structure of these particular layers that develop because of the bioactivity of certains glasses once immersed in Simulated Body Fluid (SBF). Pathological calcifications. This last topics is related to the detailed study of the Randall's plaque, nanocrystalline apatite, which is deeply involved in nephrolithiasis. As a matter of fact, the prevalence of stones with identifiable Randall's plaque is increasing year after year. Again, little is known about the atomic and/or mesoscopic structure of the Randall's plaque.