Progress of Structural Elucidation of Amorphous Calcium Phosphate(ACP)and Hydroxyapatite (HAp): Disorder and Surfaces as Seen by Solid State NMR

Christian Jaeger; Sergey Maltsev; Andrea Karrasch

doi:10.4028/www.scientific.net/KEM.309-311.69

Paper Titles

Formation of c-Axis Aligned Hydroxyapatite Sheet by Simultaneous Imposition of High Magnetic Field and Mold Rotation During Slip Casting Process
p.53

Preparation of Hydroxyapatite Ceramics by Hydrothermal Hot-Pressing Technique
p.57

Neutron Characterisation of Hydroxyapatite Bioceramics
p.61

Preparation and Characterization of Hydroxyapatite Microspheres with Hollow Core and Mesoporous Shell
p.65

Progress of Structural Elucidation of Amorphous Calcium Phosphate(ACP)and Hydroxyapatite (HAp): Disorder and Surfaces as Seen by Solid State NMR
p.69

Bovine Serum Albumin Adsorption on Hydroxyapatite and Biphasic Calcium Phosphate and the Correlation with Zeta Potentials and Wettability
p.73

Mesoporous Structure and Protein Adsorption Property of c-Axis Oriented Apatite Aggregates
p.77

Protein Adsorption Ability of Porous Hydroxyapatite Microparticle with Metal Ions
p.81

Effect of Mg on Surface Roughness and Protein Content of Protein-Apatite Composite Layers
p.85

HomeKey Engineering MaterialsKey Engineering Materials Vols. 309-311Progress of Structural Elucidation of Amorphous...

Progress of Structural Elucidation of Amorphous Calcium Phosphate(ACP)and Hydroxyapatite (HAp): Disorder and Surfaces as Seen by Solid State NMR

Abstract:

Solid-state Nuclear Magnetic Resonance (NMR) has been used for a detailed structural analysis of different amorphous calcium phosphate (ACP) and hydroxyapatite (HAp) samples. For ACP the NMR data reveal the presence of hydrogenphosphate units in much larger quantities as known previously also showing differences between the samples. Furthermore, phosphate units close to water and a third group (yet unknown) are found in the spectra. A novel proposal has been established to explain the Ca-deficiency in nanocrystalline HAp. It consists of a crystalline core of stoichiometric composition which contains only 50% of the total phosphate amount. The residual phosphate is contained in a disordered surface layer with about 1 nm thickness. Most importantly, this surface layer contains hydrogenphosphate groups to a large extend and carbonate units. A Ca/P ratio of 1.52 is obtained from the NMR data which is very close to the value of 1.51 of the chemical analysis. Thus, NMR allows the investigation of the disordered mineral-protein interface and first examples concerning bone and nacre are presented and discussed.

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Key Engineering Materials (Volumes 309-311)

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69-72

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https://doi.org/10.4028/www.scientific.net/KEM.309-311.69

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May 2006

Authors:

Christian Jaeger, Sergey Maltsev, Andrea Karrasch

Keywords:

Amorphous Calcium Phosphate (ACP), Hydroxyapatite (HAP), NMR, Structural Investigation, Surface

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