Discerning nature's mechanism for making complex biocomposite crystals

Marine organisms have a unique ability to produce complex composite structu res at ambient temperature and pressure using inorganic materials found in nature such as calcium carbonate and organic material (e.g. proteins and po lysaccharides) produced at the cellular level. Examples of such organisms r ange from molluscs with complex mineral shells [J. Aizenberg, G. Lambert, L . Addadi, S. Weiner, Adv. Mater. 8 (1996) 222: S. Aibeek. S. Weiner, L. Add adi, Chem. Euro. J. 2 (1996) 278] to single-celled algae with ornate minera l scales [R.N. Picnaar, in: A. Winter, W.G. Siesser (Eds.), Coccolithophore s, Cambridge University Press, New York. 1994, p. 13]. Understanding the ba sic process of scale or shell formation is intrinsic to mimicking nature's biofabrication scheme. We isolated and fractionated the organic material fr om the scales of the coccolithophore algae, Pleurochrysis carterae. We anal yzed by atomic force microscopy the effects that the extracted organic mate rial has on a growing calcite crystal in situ. (C) 2000 Elsevier Science B. V. All rights reserved.