Large scale production of yolk-shell beta-tricalcium phosphate powders, and their bioactivities as novel bone substitutes

Abstract

This paper proposes the production of yolk shell structured p-tricalcium phosphate (beta-TCP) powders using a spray-drying method, suitable for commercial scale production. Spray-dried precursor powders, consisting of calcium-phosphate salts and each of the various carbon source materials, are combusted in an oxygen atmosphere to obtain a yolk shell structure. Only dextrin among the carbon source materials investigated shows promise in the production of beta-TCP yolk shell powders. By evaluating their apatite-forming capacity in simulated body fluid, the outstanding bioactivity of beta-TCP yolk shell powders is confirmed: numerous acicular and newly formed hydroxyl carbonate apatite crystals cover the entire beta-TCP surface after a single day of soaking. These crystals are observed on both the outer and inner surfaces of the shells, and on the outer surface of the core, which is encouraging for its potential use as a bone grafting material.