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Hydrothermal synthesis of hydroxyapatite nanoparticles with various counterions as templates

“…The FTIR patterns for the specimens treated in 0.1 M (NH 4 ) 2 SO 4 , 0.1 M NH 4 Cl, and 0.1 M KCl solutions (Fig. 1) are similar to each other and in agreement with that of standard hydroxyapatite powders, indicating that the ions introduced in the study do not remain in the structure of the final products, thus cause no possible averse effects in biological applications.…”

“…The solutions used were 0.1 M (NH 4 ) 2 SO 4 , 0.1 M NH 4 Cl, and 0.1 M KCl solutions respectively, with the pH value being kept at 9 by using a concentrated NH 4 OH (³35%) solution. The weight ratio of the dried precipitates to 0.1 M solutions was 1:10.…”

“…The weight ratio of the dried precipitates to 0.1 M solutions was 1:10. The suspensions were hydrothermally treated at 150 and 180°C in sealed, Teflon lined stainless steel containers for 4 h. For comparison, the white precipitates were also hydrothermally treated in NH 4 OH solution with a pH of 9 for 4 h. The resulting products were recovered by centrifuging, washed in deionised water and dried under air in an oven at 80°C.…”

“…1) are similar to each other and in agreement with that of standard hydroxyapatite powders, indicating that the ions introduced in the study do not remain in the structure of the final products, thus cause no possible averse effects in biological applications. The crystalinity of the resulting nanoparticles in 0.1 M (NH 4 ) 2 SO 4 , 0.1 M NH 4 Cl, and 0.1 M KCl solutions is examined by XRD (Fig. 2), and the samples all give the XRD pattern of the standard hydroxyapatite powder.…”

“…1) They have been used extensively for biomedical implant and bone regeneration applications, 2) and have potential uses as novel gene carriers 3) and for drug delivery. 4) Most of hydroxyapatite powders are conventionally synthesized via solidstate reactions by heat-treating such reactant mixtures as Ca(OH) 2 and Ca(H 2 PO 4 ) 2 ·H 2 O, which usually results in crystallized and agglomerated products with large grain sizes. These powders exhibit poor sintering characteristics when used to produce hydroxyapatite ceramics, and poor stability and mechanical properties of polymer-hydroxyapatite composite biomaterials when used as bioactive fillers.…”