Issue 15, 2009
From the journal:

Journal of Materials Chemistry

Calcium phosphatenanoparticles with adjustable dispersability and crystallinity

H. Urch,a   M. Vallet-Regi,b   L. Ruiz,b   J. M. Gonzalez-Calbetb  and  M. Epple*a  

* Corresponding authors

a Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitaetsstr. 5–7, Essen, Germany
E-mail: matthias.epple@uni-due.de
Fax: +49 201 1832621
Tel: +49 201 1832413

b Dept. Quimica Inorganica, Universidad Complutense, Madrid, Spain

Abstract

Approximately spherical calcium phosphate nanoparticles with a diameter of about 50 nm can be prepared by rapid precipitation from water and subsequent colloidal stabilization by coating with polymers (polyvinylpyrrolidone, PVP, and polyethyleneimine, PEI). If they are either washed with isopropanol followed by air-drying, or freeze-dried, they can be easily redispersed in polar organic solvents in colloidal form. High-resolution transmission electron microscopy (HRTEM) and electron diffraction showed that their internal crystallinity depends on the drying method: After freeze-drying, the particles remain amorphous whereas all other drying methods lead to nanocrystalline particles. TEM observations also suggest a disordered surface layer (with a thickness of about 5 nm) of the crystalline particles, consisting of hydroxyapatite and calcium oxide. The presence of calcium oxide was ascribed to a surface layer of calcium carbonate that was formed by precipitation in a hydrated surface layer from atmospheric carbon dioxide and then decarboxylated in the TEM. In conclusion, we show how calcium phosphate nanoparticles can be prepared with defined crystallinity and dispersability while their external size and shape are retained.

Graphical abstract: Calcium phosphate nanoparticles with adjustable dispersability and crystallinity

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Article information

DOI
https://doi.org/10.1039/B810026H
Article type
Paper
Submitted
13 Jun 2008
Accepted
09 Jan 2009
First published
16 Feb 2009

J. Mater. Chem., 2009,19, 2166-2171

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Calcium phosphate nanoparticles with adjustable dispersability and crystallinity

H. Urch, M. Vallet-Regi, L. Ruiz, J. M. Gonzalez-Calbet and M. Epple, J. Mater. Chem., 2009, 19, 2166 DOI: 10.1039/B810026H

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