Publications (6)18.88 Total impact
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Article: Bio-inspired citrate-functionalized apatite thin films crystallized on Ti-6Al-4V implants pre-coated with corrosion resistant layers.
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ABSTRACT: In this paper the crystallization of a bioinspired citrate-functionalized apatite (cit-Ap) thin film (thickness about 2μm) on Ti-6Al-4V supports pre-coated with bioactive and corrosion resistant buffer layer of silicon nitride (Si3N4), silicon carbide (SiC) or titanium nitride (TiN) is reported. The apatitic coatings were produced by a new coating technique based on the induction heating of the implants immersed in a flowing calcium-citrate-phosphate solution at pH11. The influence of the buffer layers and the surface roughness of the substrate on the chemical-physical features and adhesion of the cit-Ap films were investigated. The best plasticity, compactness and adherence properties have been found in the Ap layer grown on Si3N4, followed by the Ap grown on SiC and TiN, respectively. The adhesion property was likely related to the roughness of the buffered substrates, whereas the compactness and plasticity were closely related to the operating conditions during the Ap crystallization (flow rate of the solution and increase of temperature) rather than to the nature of the buffer layer.Journal of inorganic biochemistry 04/2013; · 3.25 Impact Factor -
Article: Progress on the preparation of nanocrystalline apatites and surface characterization: Overview of fundamental and applied aspects
Progress in Crystal Growth and Characterization of Materials 01/2013; 59(1):1-46. · 5.75 Impact Factor -
Article: Crystallization of bioinspired citrate-functionalized nanoapatite with tailored carbonate content.
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ABSTRACT: Novel citrate-functionalized carbonate-apatite nanoparticles with mean lengths ranging from 20 to 100 nm were synthesized by a thermal-decomplexing batch method. Needle-like and plate-shaped morphologies were obtained in the absence and presence of sodium carbonate in the precipitation medium, respectively. The precipitation time and the presence of sodium carbonate strongly affect the chemical composition as well as the dimensions and the crystallinity of nanoparticles. At a short precipitation time, poorly crystalline apatites of 100 nm mean length with a low degree of carbonation (1.5% w/w, mainly in B-position) and a high citrate content (5.9% w/w) were precipitated. This citrate content is close to that recently measured in bone apatite. When increasing the precipitation time up to 96 h the mean length and the citrate content progressively decrease and at the same time the nanoparticles become more crystalline. They are composed of a well-ordered carbonate-substituted apatitic core embedded in a non-apatitic hydrated layer containing citrate ions. This layer progressively transforms into a more stable apatite domain upon maturation in aqueous media. The nanoparticles displayed excellent compatibility properties in cell biological systems, since they were not cytotoxic to a mouse carcinoma cell line when added to a final concentration of 100 μgml(-1). This work provides new insights into the role of citrate on the crystallization of nanoapatites. Moreover, the synthesized nanoparticles are promising materials for use as nanocarriers for local targeted drug delivery systems as well as building blocks for the preparation of nanostructured scaffolds for cells in bone tissue engineering.Acta biomaterialia 05/2012; 8(9):3491-9. · 3.98 Impact Factor -
Chapter: Calcium Phosphate Surface Tailoring Technologies for Drug Delivering and Tissue Engineering and applied aspects
01/2012; -
Article: Amino Acidic Control of Calcium Phosphate Precipitation by Using the Vapor Diffusion Method in Microdroplets
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ABSTRACT: Calcium phosphate precipitation was carried out in the presence of l-aspartic acid (l-asp, iep = 2.77), l-alanine (l-ala, iep = 6.00), and l-arginine (l-arg, iep = 10.76) at different concentrations by using a vapor diffusion sitting drop method (VDSD) in microdroplets. Irrespective of the nature and the concentration of the amino acid used, the early stage in the precipitation consisted in the formation of a white viscous suspension composed of amorphous calcium phosphate (ACP) spherulites. After 1 week, different calcium phosphate phases were found depending on the amino acid nature and concentration. At higher concentrations of l-aspartic acid, brushite (dicalcium phosphate dihydrate, DCDP) platelets and a few needle-like carbonate-hydroxyapatite (HA) crystals were found. In the presence of higher concentrations of l-alanine, the precipitate was composed of both needle-like HA and octacalcium phosphate (OCP) platelets. Finally, at higher concentrations of l-arginine, we obtained carbonate-HA nanocrystals with length of 20?40 nm and a few OCP crystals, as in the blank experiment (without amino acids). The results are explained on the basis of the influence of these amino acids on the pH evolution of the solution and on the nature and strength of the interactions of the major charged species of the amino acids with the surface lattice ions of the apatite precursor phases (DCPD or OCP). A thermodynamic model, based on the temporal existence of OCP in the solution, is proposed to explain the formation of the HA nanocrystals.Crystal Growth & Design 01/2011; 11(11):4802-4809. · 4.72 Impact Factor -
Article: Biomimetic Carbonate–Hydroxyapatite Nanocrystals Prepared by Vapor Diffusion
Advanced Engineering Materials 05/2010; 12(7):B218 - B223. · 1.18 Impact Factor
