Magnesium substituted hydroxyapatite whiskers: synthesis, characterization and bioactivity evaluation

Magnesium (Mg) substituted hydroxyapatite (Mg-HAp) whiskers were hydrothermally synthesized using acetamide as a homogeneous precipitation reagent. The synthesized materials were characterized by FTIR, XRD, ICP-AES and SEM. The influence of the Mg substitution level on the lattice constants, and the stimulation of the substituted Mg ions on the proliferation of human osteoblast cells (MG-63) were investigated. The results showed that Mg-HAp whiskers with diameters of 0.2-5.0 μm and lengths up to 50 μm were obtained, and the Mg substitution amount could be well tailored by simply adjusting the initial molar ratio of Mg/(Mg + Ca) in aqueous solution. The Mg 2+ incorporated into the Ca 2+ crystal site, and the lattice constants decreased with the increase of the Mg-incorporation level. The biocompatibility of the synthetic products was confirmed by a culture of the osteoblasts in the extraction solutions and the suspensions of the whiskers. In addition, the Mg substitution could stimulate the proliferation of MG-63 at certain extracted concentrations. Moreover, the interactions of the whisker suspensions with MG-63 were characterized by SEM and fluorescence microscopy. The present study showed that the synthetic Mg-HAp whiskers might be applied as bioactive materials and mechanical reinforcements for bone tissue regenerations. Magnesium (Mg) substituted hydroxyapatite (Mg-HAp) whiskers were hydrothermally synthesized using acetamide as a homogeneous precipitation reagent.