Bioactivity of ferrimagnetic MgO–CaO–SiO2–P2O5–Fe2O3 glass-ceramics (original) (raw)
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Materials Science and Engineering: C, 2009
The structure and magnetic behaviour of 34SiO 2 -(45 − x) CaO-16P 2 O 5 -4.5 MgO-0.5 CaF 2 − x Fe 2 O 3 (where x = 5, 10, 15, 20 wt.%) glasses have been investigated. Ferrimagnetic glass-ceramics are prepared by melt quench followed by controlled crystallization. The surface modification and dissolution behaviour of these glass-ceramics in simulated body fluid (SBF) have also been studied. Phase formation and magnetic behaviour have been studied using XRD and SQUID magnetometer. The room temperature Mössbauer study has been done to monitor the local environment around Fe cations and valence state of Fe ions. X-ray photoelectron spectroscopy (XPS) was used to study the surface modification in glass-ceramics when immersed in simulated body fluid. Formation of bioactive layer in SBF has been ascertained using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The SBF solutions were analyzed using an absorption spectrophotometer. The magnetic measurements indicated that all these glasses possess paramagnetic character and the [Fe 2+ /Fe 3+ ] ions ratio depends on the composition of glass and varied with Fe 2 O 3 concentration in glass matrix. In glass-ceramics saturation magnetization increases with increase in amount of Fe 2 O 3 . The nanostructure of hematite and magnetite is formed in the glass-ceramics with 15 and 20 wt.% Fe 2 O 3 , which is responsible for the magnetic property of these glass-ceramics. Introduction of Fe 2 O 3 induces several modifications at the glass-ceramics surface when immersed in SBF solution and thereby affecting the surface dissolution and the formation of the bioactive layer.
Melt-quenched 15(ZnO,Fe 2 O 3).50SiO 2 .20(CaO,P 2 O 5).15Na 2 O bioactive glass was heat-treated at temperatures (T A) ranging from 550°C to 850°C for different time periods (t A = 1, 2, and 3 h) to understand its devitrification characteristics. Crystallization of calcium sodium phosphate, zinc ferrite, magnetite, and haematite phases depended on heat treatment conditions. Decrease in saturation magnetizations (M s) with increase in t A of glass heat-treated at T A ≥ 750°C is attributed to the formation of haematite, which is a weak magnetic material. Magnetic properties as functions of T A and t A are interpreted on the basis of clustering of Fe ions, super-exchange interaction between Fe 2+ and Fe 3+ ions, and formation of ferrimagnetic and weakly magnetic iron oxide phases with different heat treatment conditions. Electron paramagnetic resonance parameters reveal the variations in site distortions and randomness in Fe ion environment in the matrix upon heat treatment. In vitro mineralization ability of the glass-ceramics was evaluated by immersion in simulated body fluid (SBF) and monitoring both the pH variation of SBF and formation of hydroxyapatite surface layer as a function of immersion time. These studies help in assessing these glass-ceramics for hyperthermia treatment and in optimizing the processing conditions for this application.
Intriguing role of TiO2 in glass-ceramics: Bioactive and magneto-structural properties
Journal of the American Ceramic Society, 2018
We report on the structural, magnetic and bioactive properties of TiO2 modified silicate glasses. Additions of TiO 2 and heat treatment, shows remarkable and distinguishable effect on the properties of the glasses. Growth of titania-modified magnetic nanocrystals played effective role in the evolution of magnetic properties of the glass-ceramics. Some of the samples exhibit superparamagnetic nature, while others are found to be antiferromagnetic. Interestingly, after heat-treatment the magnetization trend of the samples reversed. The invitro bioactivity of these glass-ceramics was accessed by the formation of bone-like apatite structures on their surfaces after immersion in simulated body fluid (SBF). The magnetic properties along with the bioactivity of present glass-ceramics indicate their usefulness in the magnetically induced hyperthermia treatment of cancer.
Journal of Materials Science: Materials in Medicine, 2011
Magnetic bioactive glass ceramic (MG) in the system CaO-SiO 2-P 2 O 5-MgO-CaF 2-MnO 2-Fe 2 O 3 for hyperthermia treatment of bone tumor was synthesized. The phase composition was investigated by XRD. The magnetic property was measured by VSM. The in vitro bioactivity was investigated by simulated body fluid (SBF) soaking experiment. Cell growth on the surface of the material was evaluated by co-culturing osteoblast-like ROS17/2.8 cells with materials for 7 days. The results showed that MG contained CaSiO 3 and Ca 5 (PO 4) 3 F as the main phases, and MnFe 2 O 4 and Fe 3 O 4 as the magnetic phases. Under a magnetic field of 10,000 Oe, the saturation magnetization and coercive force of MG were 6.4 emu/g and 198 Oe, respectively. After soaking in SBF for 14 days, hydroxyapatite containing CO 3 2was observed on the surface of MG. The experiment of co-culturing cells with material showed that cells could successfully attach and well proliferate on MG.
Journal of Biomimetics, Biomaterials and Tissue Engineering, 2012
The Aim of this Work Is to Investigate Role of Iron in Calcium-Iron-Phosphate Bioglass. the Density, Compressive Strength, Tg Point and Leachability of Cations Were Measured. the Ph Behaviour of Simulated Body Fluid after Soaking Phosphate Glasses for Different Time Periods Were Also Studied and it Was Observed that Higher Phosphate Glasses Containing Lower Lime Possessed Better Bioactivity than Lower Phosphate Glasses Containing More Iron and Lime Contents. the DTA and FTIR Spectrometry of Glasses Were Performed. the Absorption Spectra Showed that Iron Was Present in the Glass only as Fe3+ Ion. the Leachability of Ca2+ and Fe3+ Ions from Glass Was due to Diffusion Control and P5+ Ion due to Network Break down of PO4 Tetrahedra. the DTA Peaks Were Broad. the FTIR Band around 1000 Cm-1 in Glass Was due to Asymmetric Stretching of O=P=O Linkage. the FTIR Absorption and Reflectance Spectrometry of the Glass Samples after SBF Treatment Had Confirmed the Deposition of Bone-Like Hydroxyl ...
In vitro evaluation of bioactivity of SiO2-CaO-P2O5-Na2O-CaF2-ZnO glass-ceramics
Materials Science-Poland, 2014
Zinc is an essential trace element that stimulates bone formation but it is also known as an inhibitor of apatite crystal growth. In this work addition of ZnO to SiO2-CaO-P2O5-Na2O-CaF2 glass-ceramic system was made by conventional melt-quenching technique. DSC curves showed that the addition of ZnO moved the endothermic and exothermic peaks to lower temperatures. X-ray diffraction analysis did not reveal any additional phase caused by ZnO addition and showed the presence of wollastonite and hydroxyapatite crystalline phases only in all the glass-ceramic samples. As bio-implant apatite forming ability is an essential condition, the surface reactivity of the prepared glass-ceramic specimens was studied in vitro in Kokubo’s simulated body fluid (SBF) [1] with ion concentration nearly equal to human blood plasma for 30 days at 37 °C under static condition. Atomic absorption spectroscopy (AAS) was used to study the changes in element concentrations in soaking solutions and XRD, FT-IR an...
Bioactivity of Apatite–Wollastonite Glass-Ceramics Produced by Melting Casting
Surface Review and Letters, 2013
Glass-ceramics containing only apatite and wollastonite crystals were produced in the system MgO-CaO-SiO 2 -P 2 O 5 -F by the melt casting process. The bioactivity of the glass-ceramics was determined by immersing the glass-ceramics in a simulated body°uid (SBF) and by assessing the resulting apatite formation on the free surface after various immersion durations. A 12-m-thick apatite layer formed on the surface of the glass-ceramic containing only apatite crystals after 20 days immersion in SBF. However, the thickness of the apatite layer formed on the surface of the glass-ceramic containing apatite and wollastonite crystals was 1 m. Results have shown that the bioactivity of glass-ceramic depends strongly on the type of crystal(s) developed during the glass-ceramic process and their proportion in the glassy matrix.
Preliminary comparison static and dynamic in vitro test of bioactivity of glass-ceramics
2009 2nd International Symposium on Applied Sciences in Biomedical and Communication Technologies, 2009
The bioactivity of glass ceramics from Li 2 O-SiO 2-CaO-P 2 O 5-CaF 2 system, with different amount of fluorapatite expressed as P 2 O 5 content, has been tested in vitro under static and dynamic regime. The paper reports the results of bioactivity test of glass ceramics in static and dynamic regime. XRD, SEM and EPMA analysis were used to characterise the sample as well as to detect the presence of new phase onto the surface of glass ceramics. The bioactivity, as demonstrated by the formation of new apatite layer, depends on P 2 O 5 content and testing regime. In static regime, one can observe a fine microstructure of hydroxyapatite layer on the surface on glass ceramics samples. In dynamic regime, the formation rate of this layer seems to be retarded in comparison with that of static regime.