Fabrication of mesoporous magnesium substituted β-tricalcium phosphate nanospheres by self-transformation and assembly involving EDTA ions

Mesoporous magnesium substituted beta-tricalcium phosphate (beta-TCMP) nanospheres have been fabricated by the direction of EDTA. Metastable nanoparticles were firstly grown from the amorphous Mg2P2O7. Next, the EDTA ions were adsorbed on the surface of the metastable precursor nanoparticles and controlled their self-assembly into aggregates. The adsorption of the EDTA ions increased the surface charge of the precursor nanoparticles, driving the formation of interspaces in the aggregates. Then, nucleation and growth of beta-TCMP occurred along the interspaces under the influence of EDTA. As a result, the mesoporous beta-TCMP nanospheres formed by the self-transformation of the metastable precursor nanoparticles within the aggregates. Further, the particle size and specific surface area of the obtained porous beta-TCMP nanospheres were tuned by a facile way. Interestingly, the mesoporous beta-TCMP nanospheres were capable of loading Dox with a maximum drug loading efficiency of 96.9%. The Dox-loaded mesoporous beta-TCMP nanospheres held properties of slow sustained release and easy cellular uptake. The materials could be potential biomaterials for drug delivery and tissue regeneration. (C) 2013 Elsevier Inc. All rights reserved.