resumo
We present a simple one-pot crystallization method, inspired by biological conditions, for the synthesis of hydroxyapatite (Ca(5)(PO(4))(3)OH) nanocrystals. The reaction proceeds via NH(3) vapor diffusion into a CaCl(2)-NaH(2)PO(4) mixed solution that is free of any organic additives. The advantage of relying on acidic calcium-phosphate precursors here is, first, that the reaction can be performed at room temperature within a short time and without direct pH control and, second, that it does not produce any secondary phases or byproduct. Furthermore, the addition of NaHCO(3) to the salt solution or the introduction of (NH(4))(2)CO(3) instead of NH(3) lead, respectively, to the precipitation of B- or A-type carbonate-apatite phases according to the FT-IR data. Multinuclear solid state NMR studies and especially (13)CCP experiments allow an in-depth characterization showing the presence of A/B substitutions in carbonated samples as well and indicate a close similarity to deproteinated bovine compact bone. A precipitation mechanism accounting for the precipitation of mainly A- or B-type carbonated apatite under the respective experimental conditions is proposed.
palavras-chave
CALCIUM-PHOSPHATE CRYSTALS; CARBONATED HYDROXYAPATITE; SUBSTITUTED HYDROXYAPATITE; NMR-SPECTROSCOPY; LOW-TEMPERATURE; P-31 NMR; MAS NMR; BONE; APATITES; HYDROXYLAPATITE
categoria
Chemistry; Materials Science
autores
Nassif, N; Martineau, F; Syzgantseva, O; Gobeaux, F; Willinger, M; Coradin, T; Cassaignon, S; Azais, T; Giraud-Guille, MM
Grupos
agradecimentos
We thank J. Maquet for help in the NMR studies, D. Jalabert and P. Legriel for help in the TEM studies. We are grateful to J.P. Jolivet, C. Sassoye, Belamie, F. Babonneau and C. Gervais for their scientific help. T. Azais acknowledges the Young Researcher ANR grant NanoBioMat no 06-JCJC-0089 for financial support.