March 1, 2006

NSLS Researchers Win "Best Poster" Award

At a recent Materials Research Society semi-annual meeting, an NSLS research group received a special honor. Their meeting poster, one of hundreds, was chosen as one of only six to receive a "best poster" award.

The group, which includes scientists from Stony Brook University, Brookhaven National Laboratory, and the City University of New York, is studying "biomineralization," the process by which organisms create mineralized tissues, such as bones, teeth, and shells. The collaboration includes NSLS scientist Elaine DiMasi, as well as Karthikeyan Subburaman (SBU), Nadine Pernodet (SBU), Seo-Young Kwak (BNL), Shouren Ge (SBU), Nan-Loh Yang (CUNY), and Miriam Rafailovich (SBU). They presented their poster at the MRS Fall 2005 meeting, held November 27 through December 1 in Boston, Massachusetts.

Elaine DiMasi (left) and poster presenter Karthikeyan Subburaman.

Biominerals are interesting, in part, because they are typically much stronger than ordinary minerals. As such, they may one day be used to create a new class of nanoscale composite materials. First, however, the underlying mechanisms of biomineral formation and structure must be better understood.

The group's winning poster is a summary of their research on eggshell protein mineralization. They use this as a model to study biomineralization in general, since the formation of an eggshell can be thought of as a process that includes a series of steps. First, the shell's support membrane is formed and proteins are deposited onto it. Then, the minerals that make up the shell begin to form and grow, using the protein deposits as nucleation points. Finally, the mineral forms a crystal structure on top of the protein-fiber network.

Elastin protein networks imaged by AFM (a) before mineralization and after (b) 30, (c) 60, or (d) 120 minutes of exposure to mineral. The fibrous parts of the protein become thicker and stiffer as they induce calcium carbonate mineralization.

The researchers studied this process using real "extracellular matrix proteins" - the type of proteins that make up skin tissue, for example. They used networks of these proteins as the basis of the mineralization process and then studied the mineralized proteins using a powerful imaging device called an atomic force microscope (AFM).

As described in their poster, their results show that, at the eggshell's early growth stages, only the fibrous portions of the proteins accepted calcium carbonate, the mineral. The fibers became thicker as the calcium was incorporated and, ultimately, large mineral crystals appeared. The group hopes to build on these results by learning exactly how the proteins induce the mineralization process.

ARTICLE BY: Laura Mgrdichian