Hybrid Nanoapatite by Polysaccharide Nanogel-templated Mineralization

Self-assembled nanogels of cholesterol-bearing mannan (CHM) containing phosphodiester bonds in its structure were used as templates for calcium phosphate mineralization to prepare novel organic-inorganic hybrid nanocarriers for drug-delivery systems. These hybrid materials were synthesized from a solution of calcium phosphate in the presence of CHM nanogels. The size and crystallinity of the nanomaterials were controlled by changing the calcium ion concentration. Spherical amorphous calcium phosphate (ACP) nanoparticles of similar to 20nm in size and needle- shaped hydroxyapatite (HAp) crystals similar to 80nm in length were formed from solutions of [Ca2+] = 0.8 and 2.0 mM, respectively. These hybrid nanomaterials showed excellent colloidal stability in solution, which was supported by the polymer chains of CHM on the outer surface of the hybrid nanomaterials. It was also found that an amorphous-to-crystalline transformation occurred during the formation of CHM nanogel-HAp hybrid nanomaterials.