Preparation And Characterization Of Magnetic-Fluorescent Hydroxyapatite Nanomaterials

With the development of science and technology, new functional materials have been widely used in all areas of society, especially biomaterials in biomedical fields. Hydroxyapatite (HA) is one kind of the most widely studied biomaterials with good biocompatibility and bioactivity. In order to meet the clinical demand,a novel method for the preparation of HA was developed in this paper: magnetic-fluorescent hydroxyapatite composite materials were prepared by doping rare-earth elements and magnetic particles with a simple co-precipitation method, and the properties were also charaeterized. The effect of rare-earth element doping concentration on the luminescence intensity is discussed in this paper. The main contents and results of the work are as follows:Luminescent Ln (Eu³⁺, Tb³⁺) doped hydroxyapatite nanoparticles (Eu:HA, Tb:HA) were prepared by a co-precipitation method via using the mixed solution of ammonia phosphate dibasic and calcium chlorideand, cetyltrimethylammonium bromide(CTAB) as surfactant at room temperature. The structure, morphology and optical properties were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence spectra. The obtained samples show the characteristic peaks of hydroxyapatite in a hexagonal lattice structure and exhibit rod-like morphology, the average size was 40⁵0 nm in length and 20 nm in diameter. The photoluminescence intensities (PL) of Ln:HAP can be tuned by altering the doping concentration of Ln³⁺, the optimum of Ln³⁺ is 4mol%. Moreover, the yellow and orange-emission bands with the peaks at 594 nm and 617 nm of Eu:HA were observed with ultraviolet excitation; the green-emission bands with the peak at 542 nm were observed with ultraviolet excitation. The surface area and pore volume of the samples were also analysed in this paper.The composite particles (γ-Fe₂O₃/HA) with spherical morphology were obtained by a co-precipitation method at room temperature, the average size was 30 nm in diameter; the feather-like morphologyγ-Fe₂O₃/HA were also obtained using this method at 90℃with the average size of 300 nm in length and 100 nm in diameter. X-ray diffraction (XRD) analysis revealed that both of the different morphologies ofγ-Fe₂O₃/HA are of hexagonal lattice structure without impurity phases. Magnetization measurements demonstrated thatγ-Fe₂O₃/HA composites with the different morphologies were superparamagnetic at room temperature.Bifunctional magnetic-fluorescent composite particles (γ-Fe₂O₃/Eu:HA) with spherical morphology were obtained by a co-precipitation method at room temperature, dopingγ-Fe₂O₃ and 4mol% of Eu³⁺ with the average size of 50 nm in diameter. The emissions ofγ-Fe₂O₃/Eu:HA at 594 nm and 617 nm corresponded to the ⁵D₀â†'⁷F₁, ⁵D₀â†'⁷F₂ transition respectively.