Structural characterization of nanostructured hydroxyapatite–iron oxide composites (original) (raw)
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Processing and Application of Ceramics, 2020
Nanostructured composites containing iron oxide and hydroxyapatite (m-HA) were prepared by two wet chemical methods (single-step and double-step process) having different order of magnetite and HA precipitations. The phase composition, crystal size and lattice constants of the prepared composites were determined by XRD, the functional groups by FTIR and the structure, morphology and elemental composition by TEM. The magnetic susceptibility values and the colour indexes of each composite were also determined. Biocompatibility testing was performed in simulated body fluid. The results show that the composites produced by different (single-step and double-step) co-precipitating methods show different chemical and phase composition, average particle size, and therefore different superparamagnetic properties and bioactivities, with possibilities for different applications.
Journal of Materials Science, 2012
Hydroxyapatite (HA), the main inorganic component of natural bones, is widely studied as a biomaterial due to its excellent biocompatibility and osteoinductivity. The crystal structure of HA lends itself to a wide variety of substitutions and ion doping, which allows for tailoring of material properties. In this study, iron-doped HA was synthesized via a simple ion-exchange procedure and characterized thoroughly for crystal structure and phase purity using X-ray diffraction, energy-dispersive X-ray spectroscopy, inductively coupled plasma atomic emission spectroscopy, and Fourier transform infrared spectroscopy. Magnetic properties were studied using vibrating sample magnetometer and superconducting quantum interference device analysis. Ion-exchange was attempted using both ferric and ferrous chloride iron solutions, but a substitution was only achieved using ferric chloride solution. The results showed that after iron substitution the powder retained characteristic apatite crystal structure and functional groups, but the iron-doped samples displayed paramagnetic properties, as opposed to the diamagnetism of pure HA. The effect of soaking time on iron content was also examined, and collectively X-ray diffraction and inductively coupled plasma atomic emission spectroscopy results suggested that an increase in soaking time led to an increase in iron content in the sample powder. Iron-substituted HA nanoparticles, a biomaterial with magnetic properties, could be a promising biomaterial to be used in a variety of biomedical fields, including magnetic imaging, drug delivery, or hyperthermia-based cancer treatments.
In situ synthesis of hydroxyapatite nanocomposites using iron oxide nanofluids at ambient conditions
This paper describes a simple method for the room temperature synthesis of magnetite/hydroxyapatite composite nanocomposites using ferrofluids. The in situ synthesis of magnetic–hydroxyapatite results in a homogenous distribution of the two phases as seen both in transmission electron micrographs and assembled to a micron range in the confocal micrographs. The selected area diffraction pattern analysis shows the presence of both phases of iron oxide and hydroxyapatite. To the dialyzed ferrofluid, the constituents of hydroxyapatite synthesis was added, the presence of the superparamagnetic iron oxide particles imparts directionality to the hydroxyapatite crystal growth. Electron probe microanalysis confirms the coexistence of both iron and calcium atoms. Vibrating Sample magnetometer data shows magnetization three times more than the parent ferrofluid, the local concentration of iron oxide nanoparticles affects the strength of dipolar interparticle interactions changing the energy barrier for determining the collective magnetic behavior of the sample. The limitations inherent to the use of external magnetic fields which can be circumvented by the introduction of internal magnets located in the proximity of the target by a minimal surgery or by using a superparamag-netic scaffold under the influence of externally applied magnetic field inspires us to increase the magnetization of our samples. The composite in addition shows anti-bacterial properties against the two gram (-ve) bacteria tested. This work is significant as magnetite–hydroxyapatite composites are attracting a lot of attention as adsorbents, catalysts, hyperthermia agents and even as regenerative medicine.
IOSR Journal of Applied Chemistry, 2014
Hydroxyapatite Ca 10 (PO4) 6 (OH) 2 (HA) is an important biomaterial and is the principal inorganic constituent of bones and teeth. It is also used as implant in the human body. By this investigation, hydroxyapatite nanostructured (18-56 nm) powders were prepared using novel wet precipitation method with calcium hydroxide and orthophosphoric acid solution as calcium and phosphorus precursors respectively. The Ca/P molar ratios of initial reagents are equal to 2.5. The HA filtered was dried at 90°C and calcined to different temperatures (300-1000°C). X-ray diffraction and Fourier transform infra-red spectroscopy used to characterize the calcined powder. The calcination reveals HA nano-powders. The particle size and crystallinity increase with the temperature. We note the formation of CaO at 1000°C. The refinement of cells parameters was performed by Fullprof-suite program. Thermal analysis (TG-DTA) was carried out to investigate the thermal stability of the powder.
Structural analysis of modified hydroxyapatite powders
Materials Research Bulletin, 2001
In this work, the presence of structural defects in modified hydroxyapatite (HA) samples were studied. The behavior of HA samples with different chemical compositions was compared. Structural alterations were produced by thermal treatments and high-energy milling. Electron paramagnetic resonance spectroscopy (EPR) was used in order to identify the presence of structural defects. Samples were analyzed at room temperature and the signals observed by electron paramagnetic resonance at g ϭ 1.999 were assigned to oxygen vacancies in the apatitic structure. The determination of vacancy concentration (V o •) in each sample was related with the characteristic parameters of the signal and the experimental conditions. XRD and SEM were used as additional characterization techniques. The production and concentration of these vacancies was correlated to the modifications introduced during the processing of the materials. The results were also related with the chemical composition, particle size and crystallinity of the samples.
A comparative study of hydroxyapatite nanoparticles synthesized by different routes
Química Nova, 2012
In this study, bioactive hydroxyapatite nanoparticles were prepared by two different methods: wet chemical precipitation and biomimetic precipitation. The aim was to evaluate the morphology, particle-size, crystallinity and phases of the powders obtained by traditional wet chemical precipitation and the novel biomimetic precipitation using a supersaturated calcium solution. The nanoparticles were investigated by transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The results revealed that the nanoparticles were formed by hydroxyapatite with a high crystallinity and controlled morphology. Additionally, it was found that the shape and size of the nanoparticles can be modified with each preparation method.
In vitro study of iron doped hydroxyapatite
The effect of iron substitution on the bioactivity of hydroxyapatite (HAp) under the physiological conditions was investigated. Five samples of iron doped hydroxyapatite (FeHAp) with different iron concentrations (0, 0.05, 0.1, 0.2, and 0.3 mol%) were synthesized by wet chemical method. The formation of bone-like apatite layer on the surface of the samples was detected using X-ray diffraction (XRD), Fourier transforms infrared (FTIR) and scanning electron microscope techniques. The changes of the pH of SBF medium were measured at predetermined time intervals using a pH meter. The dissolution of calcium, phosphorus and iron ions in SBF medium was determined by single beam scanning spectro-photometer. XRD and FTIR results exhibit the formation of carbonate apatite layer on the surface of the immersed samples, which increase with the increase of iron content. SEM results showed agglomeration of small crystals on the surface of the immersed samples. The solubility and dissolution tests revealed that iron doped HAp samples had a higher solubility and dissolution rate than pure sample, which indicated that iron increased the bioactivity of HAp in vitro.
Comparison of Properties of Hydroxyapatite Powders Synthesized by Chemical and Biomimetic Techniques
Acta Physica Polonica A, 2012
Hydroxyapatite [HA; Ca 10 (PO 4) 6 (OH) 2 ] which composes inorganic phase of bones and teeth is one of the biomedical materials for artificial bone, reconstruction of broken or disordered bones, coating of metallic biomedical materials and dental surgery with its great biocompatibility. In this study, HA powders were synthesized from aqueous suspensions containing H 3 PO 4 and Ca(OH) 2 with 1.67 Ca/P ratios (chemical HA, CHA) and second process is carried out in simulated body fluids consisting of (NH 4) 2 HPO 4 and Ca(NO 3) 2 •4H 2 O as biomimetic hydroxyapatite (BHA). Moreover, properties of bovine HA (BoHA) and commercial HA (CoHA) were compared with properties of synthesized HA powders. Chemical structures of synthesized powders have been examined by the Fourier transform infrared technique and X-ray diffraction. The results showed that BHA powders have a pure HA content and no secondary phase, CHA also has monetite phase as secondary phase with HA in its structure. Particle size analysis was carried out with laser particle sizer and zeta-sizer, surface area of powders has been analyzed by the Brunauer-Emmett-Teller technique. Powder morphology is determined using scanning electron microscopy. As a result two different synthesis methods affected properties of HA powders.
Synthesis and characterization of nanocrystalline hydroxyapatite by wet chemical technique
Nanocrystalline hydroxyapatite (HA) powder was synthesized by a simple heating process involving simple chemical reaction. The characterization of the produced powder showed that the powder is nanosize with particle in the range of 30-70 mm in diameter and almost evenly spherical in shape. The powder also has a high surface area of 43.16 m 2 /g. Field Emission Scanning Electron Microscopy (FESEM) observation showed the crystallite and particle size become bigger with an increment of calcination temperature, indicating increasing of crystallinity. FESEM observation showed the particle size become bigger with an increment of calcinations temperature. It is in agreement with the crystallite size analysis, obtained by Scherer's formula and particle size analysis, measured by Nano-Sizer. X-ray Diffraction (XRD) and Fourier Transform Infra Red Spectroscopy (FTIR) analyses exhibited the same result, where HA phase was clearly observed at at various temperatures up to 600˚C. However, at temperature more than 600˚C, Tri calcium phosphate (TCP) phase appeared suppressing the HA phase, producing biphasic calcium phosphate.
Journal of Thermal Analysis and Calorimetry, 2009
This paper describes the structural and morphological characterization by FT-IR spectra, X-ray diffraction pattern analysis, scanning electronic microscopy and microbiological tests, respectively of a nanomagnetite-hydroxyapatite composite (MG-HA). The magnetic properties have been also determined in order to evaluate possible applications of the composite as thermoseeds in hyperthermia therapy of bones cancer.