The mineralization process of calcium phosphate induced by the LB films of porphyrin

The Langmuir-Blodgett (LB) films of zinc(II)5,10,15,20-tetra[4-oxy(2-stearic acid) porphyrin] (ZnTSPP) was used as ordered molecular template to induce the growth of calcium phosphate crystals. This process at the surface of LB films was monitored in situ by Inverted Phase Contrast Microscopy (IPCM). It was found that the crystal morphologies changed from amorphous to regular crystal with the prolonging of the time. The transformation from unstable octacalcium phosphate (OCP) to the most stable hydroxyapatite (HAp) was confirmed. This process is step by step, which is different from the traditional epitaxial process.