Mrs. Eva Seknazi, PhD. Candidate
Biominerals are the minerals produced by living organisms. Their exceptional properties have been shown to be attributed to their intricate and hierarchical structures. Unraveling these structures and their mechanism of formation is of great importance especially for the quest to design novel bio-inspired materials.
In this study, we investigated the O. wendtii brittle star’s Mg-calcite skeletal parts. We deepened our knowledge on their structure and studied their formation mechanism, by using biomimetic synthetic systems, that allow the understanding of the influence of different isolated parameters on the crystallization pathways. Most notably, we found that this biomineral’s unique structure originates from the decomposition of its amorphous precursor, amorphous Mg-calcium carbonate, to Mg-rich particles within a low-Mg matrix. Moreover, we used biomimetic synthetic systems to study the general ability of calcium carbonate to host intracrystalline inclusions. In this context, we synthesized Ba-calcite and found that high incorporation of Ba into the calcite lattice induces a change of its symmetry, via a rotational disordering of its carbonate groups. Furthermore, we showed that Mg and Ba do not get incorporated solely into calcite, but rather, that under specific conditions of synthesis, they get incorporated into vaterite, the least stable anhydrous polymorph of calcium carbonate. Altogether, these discovered features of calcium carbonate have significant implications for the fundamental understanding of biogenic structures and for the design of novel materials.
Advisor: Prof. Boaz Pokroy
Seminar by Zoom: Click here