Highly crystalline carbonated hydroxyapatite (CHA) nanorods with different carbonate contents were synthesized by a novel hydrothermal method. The crystallinity and chemical structure of synthesized nanorods were studied by Fourier transform infrared spectroscopy (FTIR), X-ray photo-electronic spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The biocompatibility of synthesized CHA nanorods was evaluated by cell viability and alkaline phosphatase (ALP) activity of MG-63 cell line. The biocompatibility evaluation results show that these CHA nanorods are biologically active apatites and potentially promising bone-substitute biomaterials for orthopedic application.

(http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Highly crystalline carbonated hydroxyapatite (CHA) nanorods with different carbonate contents were synthesized by a novel hydrothermal method. The crystallinity and chemical structure of synthesized nanorods were studied by Fourier transform infrared spectroscopy (FTIR), X-ray photo-electronic spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The biocompatibility of synthesized CHA nanorods was evaluated by cell viability and alkaline phosphatase (ALP) activity of MG-63 cell line. The biocompatibility evaluation results show that these CHA nanorods are biologically active apatites and potentially promising bone-substitute biomaterials for orthopedic application.Keywords: Hydroxyapatite; Carbonated hydroxyapatite; Nanorods; Cell viability; Alkaline phosphatase activity; MG-63 cell BackgroundHydroxyapatite (HA) is the main inorganic component of human bone mineral, and the content of carbonate in human bone mineral is about 5-8 wt % [1, 2]. Carbonate ions in carbonated hydroxyapatites (CHA) substitute both the phosphate and hydroxyl sites of the HA structure and each is called A-type CHA and B-type CHA, respectively. Predominantly, the carbonate ions are present as B-type carbonates in natural bone minerals [3]. Synthetic CHAs have been widely used in a variety of biomedical applications including osteoconductive coatings [4][5][6], bone-substitute biomaterials [7], and vehicles for drug delivery [ 8]. Recently, hydoxyapatite nanorods have been prepared by an ethanol-induced method [9], liquid crystals [10], sonochemical synthesis [11], sol-gel method [12], and hydrothermal reaction [13,14]. However, few methods have been reported for the preparation of carbonated hydroxyapatite nanorods with different carbonate contents. Since carbonate ion substitution in the apaptite lattice plays a major role in the biochemistry and physical properties of biological apatites, it is important to develop convenient ways for the synthesis of CHA nanorods with different carbonate contents and understand how various carbonate contents affect the crystal structure and biocompatibility of CHA nanorods. Table 1 Synthesizing materials for preparing HA and CHA nanorods SamplesCaThe hydrothermal method is a typical process which has been widely used in synthesis of inorganic materials for its good repeatability and crystallinity control [15][16][17]. In this study, we developed a hydrothermal process to synthesize carbonated hydroxyapatite nanorods with different carbonate contents, using ethylene diamine tetraacetic aci...

In this study, carbonated hydroxyapatite (CHA) nanorods were prepared by a novel hydrothermal method. The crystallinity and chemical structure of synthesized CHA nanorods was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), respectively. Carmine was selected as representative organic dyes to study the adsorption capacities of CHA nanorods. Mechanistic studies of carmine adsorption by CHA nanorods show that the adsorption processes both follow the pseudo-second-order kinetic model and fit the Langmuir isotherm model well. The CHA nanorods exhibited a high adsorption capacity of 85.51 mg/g for carmine at room-temperature. The experimental results prove that CHA nanorods can be promising absorbents for removing organic dye pollutants in wastewater from paper and textile plants.

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