The role of organic/inorganic interfaces in a biological single crystal growth/carbon sequestration process.
EMSL Project ID
48131
Abstract
In this rapid access proposal, we aim to corroborate experiments by graduate students Ching-Hsuan Wu and Emilie Campbell that challenge the currently accepted model of calcite (CaCO3) single crystal growth in the sea urchin embryo, arguably one of the most important model systems for mechanistic studies of the biology and materials science of biomineralization. Briefly, using a combination of etching experiments and conventional scanning transmission electron microscopy (STEM), we find three-fold symmetric patterns of low-Z material occluded in the crystal. This is evidence for faceted growth parallel to the calcite [001] direction that contradicts the established model of a solid-state transformation (“secondary nucleation”) from a metastable amorphous precursor. While there is a significant amount of circumstantial evidence that the occluded material is organic, we have not been able to provide direct proof. Furthermore, while the symmetry in which the patterned low-Z material is present in the single crystal is highly suggestive of incorporation at the edges between {10l} facets, we currently lack 3D information that would allow us to prove this model and identify the specific facets.Consequently, we request support for a limited set of experiments using a) nanoSIMS for unambiguous proof for the presence and patterning or organic macromolecules in the inorganic single crystal and b) aberration-corrected STEM imaging, stereo-pairs, and (if possible) tomography of cross and longitudinal sections of the sea urchin embryo body rod. These data are required before October 31, 2013, for the following reasons: I) Ching-Hsuan Wu will graduate and leave the Joester group; II) The competitive renewal grant to NSF-BMAT for PI Joester is due at NSF on this date. As we have extensive prior experience with the specific samples and preliminary data using ordinary STEM, we are confident that the experiments will be successful in a short amount of time. The data generated as part of this proposal will be used as corroborating information in a publication for which we finalized all but the experiments lined out in this proposal. An advanced draft of a manuscript exists as part of the thesis requirements for Ching-Hsuan Wu. Having the corroborating data for the manuscript would allow us to publish in a high impact journal. At least one of the graduate students will travel to EMSL/PNNL to perform experiments with the support staff. If successful, we will use the data generated to prepare a theme proposal at the next deadline.
Project Details
Project type
Limited Scope
Start Date
2013-10-21
End Date
2013-12-02
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members