Biomineralization
Overview
Background:
The formation of minerals by organisms - biomineralization
- is a widespread and fascinating phenomenon. Almost 70 different mineral
types are known to be formed by organisms from all the kingdoms. These minerals
adopt complex and genetically determined shapes, are often aligned to form
arrays, and they fulfil many different functions. These include the mechanical
functions of exo- and endo-skeletons, navigation in the earth's magnetic
field, orientation in the gravity field, temporary storage, stiffening of
soft tissues and much more. For an overview of the subject, see the book
by Lowenstam and Weiner (1989) entitled On Biomineralization and the book
by Mann (2001) entitled Biomineralization.
Goals:
My long term research goals in biomineralization are to understand the underlying mechanisms that organisms from different taxa use to control mineral formation. A second focus is to understand the structure - mechanical function relations of mineralized tissues. The former research is done in collaboration with Prof Lia Addadi, (Dept. Structural Biology) and the latter with Profs Friesem, Wagner and Dr Ron Shahar.
Approaches:
Controlled Mineral Formation
 |
| Model of the mollusk shell organic matrix proposed by Weiner and Traub (1984) (left hand side) compared to the new model based on cryo-TEM proposed by Levi et al (2001) J. Struct. Biol. 135, 8-17 (right hand side). |
The research is problem oriented. We thus choose biological systems that we think can offer us the best opportunity to solve the question on hand. We are and have thus worked on mollusks, echinoderms, sponges, crustaceans, ascidians, plants and vertebrates. We try to solve problems by integrating information on the structure, the matrix biochemistry, and the mineral phase of the natural tissues. We also devise in vitro experiments aimed at elucidating mechanisms involved in the biological processes. The most commonly used analytical instrumentation is scanning and transmission electron microscopy (especially in the hydrated mode), X-ray diffraction, EXAFS, infrared and Raman spectroscopy, a range of biochemical techniques, and most recently also molecular biological methods.
Structure-Function Relations
| Hierarchical structure of bone. For more information see Weiner and Wagner 1988, Annual Review of Materials Science 28, 271-298. |
 |
 |
 |
Mineralized tissues often have complex hierarchical structures, and many of these fulfil a mechanical function. Thus a second major interest is to understand their structures in relation to the mechanical functions they fulfil. In this regard, much of the research is focussed on lamellar bone, which is also the most common form of bone in humans. The research has implications to better understanding osteoporosis and other bone diseases. We are currently studying the structure-mechanical relations of whole human teeth, in order to elucidate tooth function. We are using holographic and speckle interferometry to map strain of teeth subjected to compressive forces that occur during mastication. This research has implications to dentistry.
Weizmann Institute of Science, Rehovot, 76100 Israel
Tel: (972)-8-9342552;
Fax: (972)-8-9344136;
Email: steve.weiner@weizmann.ac.il
)
)