The formation of highly organized biogenic polymer/ceramic composite materials: The high-performance microaluminate of molluscan nacre

Nucleation of aragonitic nacre in molluscan shells was thought to be an epitactic process where sheets of organic material act as a mediator of the underlying crystal phase. Recent experiments show that the mineral itself might grow through pores in the organic sheets forming mineral bridges to continue the single crystal from one layer to the other. Crystal phases of calcite may be switched under in vitro conditions depending on the proteins incubated with the inorganic ions in the growth solution. The purified proteins from molluscan shells have been used to grow calcite or aragonite and kinetic studies performed with atomic force microscopy gave insight into the growth process. Those experiments are important steps towards a synthetic material containing the same high performance properties as molluscan nacre.