Ion bonding in organic scaffolding promotes biomineralization
- PDF / 455,190 Bytes
- 2 Pages / 585 x 783 pts Page_size
- 76 Downloads / 176 Views
ding in organic scaffolding promotes biomineralization
T
he seashells you pick up at the beach might not seem extraordinary, but they are a source of inspiration for researchers searching for efficient ways to store extra atmospheric carbon. Through a process called biomineralization, organisms like mollusks, clams, and corals crystallize excess carbon in their environment into hard calcium carbonate shells. Understanding on a molecular level the way that inorganic minerals interact with a framework of biological macromolecules is a critical step toward mimicking the process in artificial systems—and one that has proven challenging. Now, an international team of materials researchers has demonstrated that these organic scaffolds influence the crystallization process by binding clusters of positively charged calcium ions, inducing mineral formation in specific locations. The results, published recently in Nature Materials, challenge previous assumptions about the molecular-level mechanisms responsible for biomineralization. “This work is of great value in the realm of fundamental materials science—in particular in the world of living systems, where soft matter controls hard matter,” said Jim De Yoreo of Pacific Northwest National Laboratory. De Yoreo and his colleagues used liquid-phase transmission electron microscopy (TEM)—a relatively new imaging technology that visualizes atomic-level
200
MRS BULLETIN
•
VOLUME 40 • MARCH 2015
•
modulation of the functional properties of the spinal cord and brain,” says Reggie Edgerton, a bioengineer at the University of California–Los Angeles, who wasn’t involved in the work. “It is now apparent that there can be multiple strategies to neuromodulate the spinal cord and brain, ranging from indwelling electrodes within the spinal cord to stimulating transcutaneously. Ideally, each can be developed to include in a clinical toolbox from which the best option for a given patient under a given situation
activity in liquid samples—to monitor the crystallization process in real time at nanoscale resolution. They first observed vaterite and a little bit of calcite, two different calcium carbonate crystal structures, forming in a solution in the TEM. Then, they repeated the experiment with added polystyrene sulfonate (PSS), an organic polymer with negatively charged side chains that is structurally similar to the macromolecules that guide biomineralization in natural systems. This time, the mineralization process looked different: Amorphous calcium carbonate (ACC) formed first, then later transformed into vaterite. ACC is a precursor to many biologically based minerals. To understand how the PSS scaffold interfered with vaterite formation, the researchers mixed the calcium with the macromolecules without the carbonate. The macromolecules clumped together, absorbing the calcium ions to form globules. Once the carbonate was added, ACC crystals only formed within the calcium-PSS globules, and stopped growing once the calcium ran out. The finding suggested to the team that calcium bind
Data Loading...
