Preparation and characterization of new hybrid organic/inorganic systems derived from calcium (aminoalkyl)-phosphonates and -phosphonocarboxylates

Laboratoire des IMRCP (UMR CNRS No 5623), Université Paul Sabatier 118, route de Narbonne, Bât. 2R1, 31062 Toulouse cedex 04, France.
Journal of Colloid and Interface Science (Impact Factor: 3.37). 10/2005; 289(2):504-11. DOI: 10.1016/j.jcis.2005.03.095
Source: PubMed

ABSTRACT We have studied the phenomenon of calcium complexation by lab synthesized amphiphilic (alpha-aminoalkyl)-phosphonocarboxylic or -phosphonic acids. The electrical conductivity of aqueous solutions of sodium salts of all these acids was measured versus the volume of a calcium salt solution added. It appeared that calcium complexes are formed in a Ca/P atomic ratio close to 1. Calcium phosphonocarboxylates and calcium phosphonates were also precipitated by mixing aqueous solutions of disodium salts of phosphorus amphiphiles and calcium nitrate solutions. Before chemical analysis, these complexes were calcined to remove the organic part. In the mineralized products, calcium and phosphate were assayed: the Ca/P atomic ratio was equal to 1. X-ray diffraction and IR spectroscopy showed that they are made entirely of beta pyrophosphate (Ca2P2O7), a result in agreement with previous chemical analysis. The chemical formula of the starting calcium complexes could be written as CaL2H2O (L=ligand). The SEM micrographs of these complexes show plate-like structures. XRD patterns are characteristic of layered structures. These facts suggest that calcium complexes are composed of alternating bimolecular layers of calcium alkylphosphonocarboxylates or calcium alkylphosphonates, the chains being tilted and partially interdigitated.

4 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: To achieve the injectable hydrogel system in order to improve bone regeneration by locally delivering a protein drug including bone morphogenetic proteins, thermo-responsive injectable hydrogels composed of N-isopropylacrylamide (NIPAAm) and vinyl phosphonic acid (VPAc) were prepared. The P(NIPAAm-co-VPAc) hydrogels were also biomineralized by urea-mediation method to create functional polymer hydrogels that deliver the protein drug and mimic the bone extracellular matrix. The loosely cross-linked P(NIPAAm-co-VPAc) hydrogels were pliable and fluid-like at room temperature and could be injected through a small-diameter aperture. The lower critical solution temperature (LCST) of P(NIPAAm-co-VPAc) hydrogel was influenced by the monomer ratio of NIPAAm/VPAc and the hydrogel with a 96/4 molar ratio of NIPAAm/VPAc exhibited an LCST of ∼34.5°C. Water content was influenced by temperature, NIPAAm/VPAc monomer ratio, and biomineralization; however, all hydrogels maintained more than about 77% of the water content even at 37°C. In a cytotoxicity study, the P(NIPAAm-co-VPAc) and biomineralized P(NIPAAm-co-VPAc) hydrogels did not significantly affect cell viability. The loading content of bovine serum albumin in hydrogel, which was used as a model drug, gradually increased with the amount of VPAc in the hydrogel owing to the ionic interaction between VPAc groups and BSA molecules. In addition, the release behavior of BSA from the P(NIPAAm-co-VPAc) hydrogels was mainly influenced by the drug loading content, water content, and biomineralization of the hydrogels. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
    Journal of Applied Polymer Science 09/2009; 113(6):3460 - 3469. DOI:10.1002/app.30318 · 1.77 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The preparation of apatite-alendronate hybrid materials by reactive milling is proposed in this work. Calcium phosphate compounds of various compositions have been associated to bisphosphonates and found suitable for local application with release kinetics of the drug compatible with the inhibition of bone resorption. Hybrid compounds have been obtained by reactive milling. The compositions used were: AP(X-100), Alendronate(X) where X=7 and X=15. An interaction between the hydroxyl group of the apatite and the amine group of alendronate can be identified with FTIR and enables to confirm the formation of the hybrids. The incorporation of the alendronate hinders the growing of the apatite crystals resulting in smaller coherent domains of diffraction for the apatite phase. © 2012 Elsevier Ltd and Techna Group S.r.l.
    Ceramics International 05/2013; 39(4-4):3921-3929. DOI:10.1016/j.ceramint.2012.10.239 · 2.61 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The electroplating of Re-Ni alloys in citrate electrolytes of different compositions was studied by cyclic voltammetry and by anodic stripping voltammetry, following galvanostatic deposition. The faradaic efficiency of the deposition process and the composition of the deposits were determined. Increasing the concentrations of either the nickel or the perrhenate ion in the electrolytes was shown to enhance the rate of deposition of the Re-Ni alloy. The process is influenced by mass transport and by concentration of citric acid in the electrolytes. Conductometry, UV-Vis and Raman spectroscopy were used for studying the ionic interactions in electrolytes. No evidence of the existence of perrhenate complexes with other components of the electrolyte was found. However, an increased deformation of the perrhenate ions with increasing molar ratio of [NiCit](-)/ReO4- was clearly shown by Raman spectroscopy. Hence, a weak interaction is definitely observed, which is enough to distort the shapes of the ReO4- and [NiCit](-) or [NiHCit] species, thus enhancing the deposition rate of the Re-Ni alloy. The induced co-deposition is believed to be a catalytic process, including the stage of simultaneous reduction of ReO4- and [NiCit]- or [NiHCit] species, which influences each other by weak interaction. (c) 2014 The Electrochemical Society. All rights reserved.
    Journal of The Electrochemical Society 08/2014; 161(12):D632-D639. DOI:10.1149/2.0071412jes · 3.27 Impact Factor


4 Reads
Available from