Biomimetic gelatin–octacalcium phosphate core–shell microspheres.

Calcium phosphate/polymeric microparticles synthesized through a biomimetic approach are regarded with increasing interest for their various potential applications, including tissue engineering and regenerative medicine. Herein we report the synthesis and characterization of gelatin/octacalcium phosphate core/shell microspheres. Deposition of the calcium phosphate shell on the polymeric microspheres was obtained through bio-inspired mineralization on the surface of functionalized gelatin microparticles. Gelatin microspheres stabilized by alginate dialdehyde were prepared using an inverse microemulsion. Functionalization was achieved by enriching the microspheres composition with calcium ions or, alternatively, with alendronate, a bisphosphonate widely employed for the treatment of bone diseases. Functionalization and synthesis of the inorganic phase in the microemulsion environment were key factors for the achievement of a complete coating of the microspheres with calcium phosphate. The inorganic shell is constituted of small crystals of octacalcium phosphate, which control gelatin and alendronate release.