Biomimetic approach for strontium-containing Ca-P bioceramics with enhanced biological activity

Trace elements are an interesting alternative to growth factors in order to favour bone formation and among them, strontium has been shown to improve bone formation in osteoporotic patients. The location of strontium in bone varies with age and the type of bone tissues. High strontium uptakes were always found to be associated with recent mineral formations rich in labile non-apatitic environments. Synthetic poorly crystalline apatites (PCA) with similar properties were prepared. The uptake of Sr2+ ions depends on the maturation stage of the crystals. Freshly precipitated synthetic apatites participated more efficiently in exchange. Most Sr2+ ions could be easily released, like in bone mineral crystals, but a small fraction was irreversibly bound. PCA can be used as an ion reservoir for labile strontium ions with potential biological activity.