Spatial and temporal Study of assembly of organic matrix and their roles in mineral nucleation
EMSL Project ID
48114
Abstract
Self-assembled protein architectures exhibit diverse structural motifs including particles, fibers, ribbons and sheets. Their functions include selective transport, structural scaffolding, templated mineral nucleation, and propagation or protection from pathogenesis, all of which are believed to be highly structure-related [1-4]. Especially, the highly ordered protein architecture inside biominerals is believed to guide crystal nucleation and alignment and endow biominerals with remarkable mechanical properties [5]. Dentin and bone contain a higher percentage of organic constituents than mature dental enamel with type I collagen being the primary matrix component [5, 6]. In contrast, mature enamel contains about 97% of highly ordered mineral and has little organic content, with numerous proteins like amelogenin, enamelin and MMP-20 believed to play crucial roles at various mineralization stages but become digested by the end of the process [7-11]. Many in vitro studies have investigated mineralization on collagen or amelogenin, but have not studied the earliest CaP nucleation events responsible for subsequent orientation, complex morphology and specific mineral phase within dentin, bone and enamel. In this proposal, we will use bound forms of OPN and other smaller peptides on collagen surfaces to investigate the roles played by these proteins in templated nucleation of CaP. We also use assembled amelogenin as a template to study CaP nucleation and alignment in the presence of enamelin and MMP-20 at different stages. The thermodynamic and kinetic mechanisms responsible for CaP nucleation events before formation of hydroxyapatite (HAP) on collagen or amelogenin will be investigated using in situ AFM investigations to obtain direct molecular-level imaging of nucleation events and post-nucleation morphological and phase evolution, as well as area-specific nucleation rates as a function of supersaturation.
Project Details
Start Date
2013-07-25
End Date
2013-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Shin Y, J Tao, BW Arey, C Wang, GJ Exarhos, JJ De Yoreo, ML Sushko, and J Liu. 2016. "Double epitaxy as a paradigm for templated growth of highly ordered three-dimensional mesophase crystals." ACS Nano 10(9):8670–8675. doi:10.1021/acsnano.6b03999