Selective in vitro effect of peptides on calcium carbonate crystallization

Peptides carried by filamentous phages with potential affinity to calcium carbonate were selected experimentally from a phage display library. The isolated phage were employed to affect the precipitation of calcium carbonate from aqueous solution. SEM, FTIR, and confocal microsopy techniques were used to monitor the morphology and polymorph development of calcium carbonate crystallization. Hollow spheres consisting of nanoscale vaterite crystallites were obtained, which may be due to the template effect of the phage. These spherical crystals transformed into rhombic calcite crystals with time, a process that was slowed by the presence of phage. It is proposed that this phase transformation is a solution-mediated process.