Titel
Assessing the Onset of Calcium Phosphate Nucleation by Hyperpolarized Real-Time NMR
Autor*in
Emmanuelle M. M. Weber
Radiological Sciences Laboratory, Department of Radiology, Stanford University, Richard M. Lucas Center for Imaging
Autor*in
Daniel Abergel
Laboratoire des biomolécules (LBM), Département de chimie, École normale supérieure, PSL University, Sorbonne Université, CNRS
... show all
Abstract
We report an experimental approach for high-resolution real-time monitoring of transiently formed species occurring during the onset of precipitation of ionic solids from solution. This is made possible by real-time nuclear magnetic resonance (NMR) monitoring using dissolution dynamic nuclear polarization (D-DNP) to amplify signals of functional intermediates and is supported by turbidimetry, cryogenic electron microscopy, and solid-state NMR measurements. D-DNP can provide drastic signal improvements in NMR signal amplitudes, permitting dramatic reductions in acquisition times and thereby enabling us to probe fast interaction kinetics such as those underlying formation of prenucleation species (PNS) that precede solid–liquid phase separation. This experimental strategy allows for investigation of the formation of calcium phosphate (CaP)-based minerals by 31P NMR—a process of substantial industrial, geological, and biological interest. Thus far, many aspects of the mechanisms of CaP nucleation remain unclear due to the absence of experimental methods capable of accessing such processes on sufficiently short time scales. The approach reported here aims to address this by an improved characterization of the initial steps of CaP precipitation, permitting detection of PNS by NMR and determination of their formation rates, exchange dynamics, and sizes. Using D-DNP monitoring, we find that under our conditions (i) in the first 2 s after preparation of oversaturated calcium phosphate solutions, PNS with a hydrodynamic radius of Rh ≈ 1 nm is formed and (ii) following this rapid initial formation, the entire crystallization processes proceed on considerably longer time scales, requiring >20 s to form the final crystal phase.
Stichwort
AggregationCrystallizationNuclear magnetic resonance spectroscopyPhosphatesPrecipitation
Objekt-Typ
Sprache
Englisch [eng]
Persistent identifier
Erschienen in
Titel
Analytical Chemistry
Band
92
Ausgabe
11
ISSN
0003-2700
Erscheinungsdatum
2020
Seitenanfang
7666
Seitenende
7673
Publication
American Chemical Society (ACS)
Projekt
Kod / Identifikator
801963
Erscheinungsdatum
2020
Zugänglichkeit
Rechteangabe
© 2020 American Chemical Society

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