Synthesis of nanogranular Fe3O4/biomimetic hydroxyapatite for potential applications in nanomedicine: structural and magnetic characterization. (5th June 2015)

• Record Type: Journal Article
• Authors: Bianco, L Del; Lesci, I G; Fracasso, G; Barucca, G; Spizzo, F; Tamisari, M; Scotti, R; Ciocca, L
• Is Part Of: Materials research express. Volume 2:Number 6(2015)
• Publication Date: 2015-06-05
• Subjects: biocompatible magnetic material -- magnetite nanoparticles -- biomimetic hydroxyapatite; Materials science -- Research -- Periodicals; Materials science -- Periodicals; 620.11
• DOI: 10.1088/2053-1591/2/6/065002
• Languages: English
• ISSNs: 2053-1591

Abstract

Abstract: We realized the synthesis of a novel nanogranular system consisting of magnetite nanoparticles embedded in biomimetic carbonate hydroxyapatite (HA), for prospective uses in bone tissue engineering. An original two-step method was implemented: in the first step, magnetite nanoparticles are prepared by refluxing an aqueous solution of Fe(SO4 ) and Fe2 (SO4 )3 in an excess of tetrabutilammonium hydroxide acting as surfactant; then, the magnetite nanoparticles are coated with a Ca(OH)2 layer, to induce the growth of HA directly on their surface, by reaction of Ca(OH)2 with HPO4 2− . Two nanogranular samples were collected with magnetite content ∼0.8 and ∼4 wt%. The magnetite nanoparticles and the composite material were investigated by x-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy. These analyses provided information on the structure of the nanoparticles (mean size ∼6 nm) and revealed the presence of surface hydroxyl groups, which promoted the subsequent growth of the HA phase, featuring a nanocrystalline lamellar structure. The magnetic study, by a superconducting quantum interference device magnetometer, has shown that both the as-prepared and the HA-coated magnetite nanoparticles are superparamagnetic at T = 300 K, but the magnetization relaxation process is dominated by dipolar magnetic interactions of comparable strength. In the three samples, a collective frozen magnetic regime is established below T ∼ 20 K. These results indicate that the magnetite nanoparticles tend to form agglomerates in the as-prepared state, which are not substantially altered by the HA growth, coherently with the creation of electrostatic hydrogen bonds among the surface hydroxyl groups.