Fabrication of Uniform Casein/CaCO3 Vaterite Microspheres and Investigation of Its Formation Mechanism

Abstract

Uniform Casein/CaCO3 microspheres were fabricated with well tuned properties and the formation mechanism based on the templating effect of casein micelles was proposed. In bone tissue engineering, vaterite microspheres were promising because of the biocompatibility and easy fabrication. Here Casein/CaCO3 microspheres were precipitated by mixing CaCl2 and Na2CO3 solutions under stirring in the presence of casein. All samples were mainly in vaterite, composed of aggregates of nanosized crystals. With the increase of casein concentration, the amount of calcite and microsphere size decreased while the loading content of casein increased, suggesting that casein induced the formation of vaterite and also stabilized the crystal phase. The formation mechanism was further investigated. With the increase of CaCl2 amount, the size of the forming microspheres increased while the zeta potential was stabilized, the polycrystalline nature was shown, and the presence of Ca inside microspheres was confirmed. Hence, the fo...