Calcium phosphate crystallization on polyglycine, polytyrosine and polymethionine

The kinetics of hydroxyapatite (HAP) crystallization on the polyaminoacids polyglycine, polytyrosine, polymethionine, was investigated by the constant composition technique. The apparent order for the crystallization process was found to be 2, indicative of a surface diffusion control mechanism. There are three possible mechanisms for critical nucleus formation with size n* = 3 ± 1 as defined by computational chemistry calculations at 310 K. The calculated surface energy from kinetic data for the growing HAP phase was 109 ± 15 mJ m− 2.