Wang, Y-W, Christenson, HK and Meldrum, FC (2014) Confinement increases the lifetimes of hydroxyapatite precursors. Chemistry of Materials, 26 (20). 5830 - 5838. ISSN 0897-4756
Abstract
The mineral component of bone is a carbonated, nonstoichiometric hydroxyapatite (calcium phosphate) that forms in nanometer confinement within collagen fibrils, the principal organic constituent of bone. We here employ a model system to study the effects of confinement on hydroxyapatite precipitation from solution under physiological conditions. In common with earlier studies of calcium carbonate and calcium sulfate precipitation, we find that confinement significantly prolongs the lifetime of metastable phases, here amorphous calcium phosphate (ACP) and octacalcium phosphate (OCP). The effect occurs at surprisingly large separations of up to 1 μm, and at 0.2 μm the lifetime of ACP is extended by at least an order of magnitude. The soluble additive poly(aspartic acid), which in bulk stabilizes ACP, appears to act synergistically with confinement to give a greatly enhanced stability of ACP. The reason for the extended lifetime appears to be different from that found with CaCO3 and CaSO4, and underscores both the variety of mechanisms whereby confinement affects the growth and transformation of solid phases, and the necessity to study a wide range of crystalline systems to build a full understanding of confinement effects. We suggest that in the case of ACP and OCP the extended lifetime of these metastable phases is chiefly due to a slower transport of ions between a dissolving metastable phase, and the more stable, growing phase. These results highlight the potential importance of confinement on biomineralization processes.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | This document is the Accepted Manuscript version of a Published Work that appeared in final form in Chemistry of Materials copyright © American Chemical Society 2014 after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/cm501770r |
Keywords: | Amorphous calcium phosphate; octacalcium phosphate; biomineralization; bio-mimetic; bio-inspired; crystallization |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 09 Mar 2015 10:56 |
Last Modified: | 30 Jun 2020 14:49 |
Published Version: | http://dx.doi.org/10.1021/cm501770r |
Status: | Published |
Publisher: | American Chemical Society |
Identification Number: | 10.1021/cm501770r |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:83531 |