Assembly of aqueous-cored calcium phosphate nanoparticles for drug delivery

A synthesis strategy for aqueous-cored calcium phosphate nanoparticles is presented that combines ease of preparation, reproducibility, size control, stability, and mean thickness control. Suspension stability and shell thickness control were achieved through the introduction of a "capping" molecule, carboxyethylphosphoric acid (CEPA). Using this method, suspensions of calcium phosphate shells were produced with a size distribution of 120-185 +/- 50 nm and predictable mean shell thickness from 10 to 40 nm that were stable up to a month, even in the presence of 200 mMsalt and 2.5 g/dL albumin.