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Structural and Chemical Hierarchy in Hydroxyapatite Coatings

Hydroxyapatite coatings need similarly shaped splats as building blocks and then a homogeneous microstructure to unravel the structural and chemical hierarchy for more refined improvements to implant surfaces. Coatings were thermally sprayed with differently sized powders (20–40, 40–63 and 63–80 µm)...

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Autores principales: Gross, Karlis A., Petzold, Christiane, Pluduma-LaFarge, Liene, Kumermanis, Maris, Haugen, Håvard J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7579587/
https://www.ncbi.nlm.nih.gov/pubmed/33036441
http://dx.doi.org/10.3390/ma13194447
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author Gross, Karlis A.
Petzold, Christiane
Pluduma-LaFarge, Liene
Kumermanis, Maris
Haugen, Håvard J.
author_facet Gross, Karlis A.
Petzold, Christiane
Pluduma-LaFarge, Liene
Kumermanis, Maris
Haugen, Håvard J.
author_sort Gross, Karlis A.
collection PubMed
description Hydroxyapatite coatings need similarly shaped splats as building blocks and then a homogeneous microstructure to unravel the structural and chemical hierarchy for more refined improvements to implant surfaces. Coatings were thermally sprayed with differently sized powders (20–40, 40–63 and 63–80 µm) to produce flattened homogeneous splats. The surface was characterized for splat shape by profilometry and Atomic force microscopy (AFM), crystal size by AFM, crystal orientation by X-ray diffraction (XRD) and structural variations by XRD. Chemical composition was assessed by phase analysis, but variations in chemistry were detected by XRD and Raman spectroscopy. The resulting surface electrical potential was measured by Kelvin probe AFM. Five levels of structural hierarchy were suggested: the coating, the splat, oriented crystals, alternate layers of oxyapatite and hydroxyapatite (HAp) and the suggested anion orientation. Chemical hierarchy was present over a lower range of order for smaller splats. Coatings made from smaller splats exhibited a greater electrical potential, inferred to arise from oxyapatite, and supplemented by ordered OH(−) ions in a rehydroxylated surface layer. A model has been proposed to show the influence of structural hierarchy on the electrical surface potential. Structural hierarchy is proposed as a means to further refine the properties of implant surfaces.
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spelling pubmed-75795872020-10-29 Structural and Chemical Hierarchy in Hydroxyapatite Coatings Gross, Karlis A. Petzold, Christiane Pluduma-LaFarge, Liene Kumermanis, Maris Haugen, Håvard J. Materials (Basel) Article Hydroxyapatite coatings need similarly shaped splats as building blocks and then a homogeneous microstructure to unravel the structural and chemical hierarchy for more refined improvements to implant surfaces. Coatings were thermally sprayed with differently sized powders (20–40, 40–63 and 63–80 µm) to produce flattened homogeneous splats. The surface was characterized for splat shape by profilometry and Atomic force microscopy (AFM), crystal size by AFM, crystal orientation by X-ray diffraction (XRD) and structural variations by XRD. Chemical composition was assessed by phase analysis, but variations in chemistry were detected by XRD and Raman spectroscopy. The resulting surface electrical potential was measured by Kelvin probe AFM. Five levels of structural hierarchy were suggested: the coating, the splat, oriented crystals, alternate layers of oxyapatite and hydroxyapatite (HAp) and the suggested anion orientation. Chemical hierarchy was present over a lower range of order for smaller splats. Coatings made from smaller splats exhibited a greater electrical potential, inferred to arise from oxyapatite, and supplemented by ordered OH(−) ions in a rehydroxylated surface layer. A model has been proposed to show the influence of structural hierarchy on the electrical surface potential. Structural hierarchy is proposed as a means to further refine the properties of implant surfaces. MDPI 2020-10-07 /pmc/articles/PMC7579587/ /pubmed/33036441 http://dx.doi.org/10.3390/ma13194447 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Gross, Karlis A.
Petzold, Christiane
Pluduma-LaFarge, Liene
Kumermanis, Maris
Haugen, Håvard J.
Structural and Chemical Hierarchy in Hydroxyapatite Coatings
title Structural and Chemical Hierarchy in Hydroxyapatite Coatings
title_full Structural and Chemical Hierarchy in Hydroxyapatite Coatings
title_fullStr Structural and Chemical Hierarchy in Hydroxyapatite Coatings
title_full_unstemmed Structural and Chemical Hierarchy in Hydroxyapatite Coatings
title_short Structural and Chemical Hierarchy in Hydroxyapatite Coatings
title_sort structural and chemical hierarchy in hydroxyapatite coatings
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7579587/
https://www.ncbi.nlm.nih.gov/pubmed/33036441
http://dx.doi.org/10.3390/ma13194447
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