Evolution of Magnetic and Bone Mineral Phases in Heat-Treated Bioactive Glass Containing Zinc and Iron Oxides (original) (raw)
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Three samples of glass/ceramic composites were prepared from bioactive phosphate glass and iron oxide. The composite samples contained 30, 50, and 70 mass-% Fe2O3. Within the samples, the formation of a hematite phase in the glass matrix allows the composites to be responsive to a magnetic field when used for hyperthermia as a cancer treatment. In the present study, the addition of bioactive glass to the ceramic gives the composite samples their bioactive properties, which are needed for the implantation of samples in human bone. The two other phases – sodium phosphate and calcium phosphate – are responsible for this bioactive behavior. In addition, changes in magnetic phase percent in the samples affect their magnetic properties.
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.
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.
Bioactivity of ferrimagnetic MgO–CaO–SiO2–P2O5–Fe2O3 glass-ceramics
Ceramics International, 2010
Glass-ceramics with compositions 4.5MgO(45 À x)CaO34SiO 2 16P 2 O 5 0.5CaF 2 xFe 2 O 3 (where x = 0, 5, 10, 15 and 20 wt.%) were obtained by heat-treatment of melt quenched glasses at 1050 8C. Hydroxyapatite, magnetite and wollastonite were identified as major crystalline phases in all the glass-ceramic samples containing iron oxide. Akermanite was detected in glass-ceramic samples with high iron oxide content. Evolution of magnetic properties in the glass-ceramic samples as a function of iron oxide concentration is correlated with the amount of magnetite phase. Bioactivity of the glass-ceramic samples treated for various time periods in simulated body fluid (SBF) was evaluated by examining the apatite layer formation on their surface using X-ray diffraction, Fourier transform infrared reflection spectroscopy, scanning electron microscopy and energy dispersive spectroscopy techniques. Increase in bioactivity was observed as the iron oxide content was increased. The results help in understanding the evolution of the apatite surface layer with respect to immersion time in SBF and composition of the glass-ceramic samples. #
Journal of Magnetism and Magnetic Materials, 2010
Glass ceramics of the composition xZnO Á 25Fe 2 O 3 Á (40 À x)SiO 2 Á 25CaO Á 7P 2 O 5 Á 3Na 2 O were prepared by the melt-quench method using oxy-acetylene flame. Glass-powder compacts were sintered at 1100 1C for 3 h and then rapidly cooled at À 10 1C. X-ray diffraction (XRD) revealed 3 prominent crystalline phases: ZnFe 2 O 4 , CaSiO 3 and Ca 10 (PO 4 ) 6 (OH) 2 . Vibrating sample magnetometer (VSM) data at 10 KOe and 500 Oe showed that saturation magnetization, coercivity and hence hysteresis area increased with the increase in ZnO content. Nano-sized ZnFe 2 O 4 crystallites were of pseudo-single domain structure and thus coercivity increased with the increase in crystallite size. ZnFe 2 O 4 exhibited ferrimagnetism due to the random distribution of Zn 2 + and Fe 3 + cations at tetrahedral A sites and octahedral B sites. This inversion/random distribution of cations was probably due to the surface effects of nano-ZnFe 2 O 4 and rapid cooling of the material from 1100 1C (thus preserving the high temperature state of the random distribution of cations). Calorimetric measurements were carried out using magnetic induction furnace at 500 Oe magnetic field and 400 KHz frequency. The data showed that maximum specific power loss and temperature increase after 2 min were 26 W/g and 37 1C, respectively for the sample containing 10% ZnO. The samples were immersed in simulated body fluid (SBF) for 3 weeks. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDX) and XRD results confirmed the growth of precipitated hydroxyapatite phase after immersion in SBF, suggesting that the ferrimagnetic glass ceramics were bioactive and could bond to the living tissues in physiological environment.
Study of an anisotropic ferrimagnetic bioactive glass ceramic for cancer treatment
Applied Physics A-materials Science & Processing, 2010
For the hyperthermia therapy of cancer, ferrimagnetic glass ceramics are a potential candidate. Ferrimagnetic zinc-ferrite-containing bioactive glass ceramics were prepared by quenching the glass ceramics from sintering temperature. Then the samples were heated to 600°C and cooled in an aligning magnetic field of 1 Tesla to cause anisotropy. The magnetically aligned samples were compared with non-aligned samples. Vibrating sample magnetometry measurements at 10 kOe showed that the magnetic properties were enhanced by the aligning magnetic field and it led to an enhancement of the magnetic heat generation under a magnetic induction furnace operating at 500 Oe and 400 kHz for 2 min. Data showed that the maximum specific power loss and temperature increase after 2 min were 31.5 W/g and 45°C, respectively, for the aligned sample of maximum zinc-ferrite crystalline content. The glass ceramics were immersed in simulated body fluid for 3 weeks. X-ray diffraction and Fourier transform infrared and atomic absorption spectroscopy results indicated the growth of precipitated hydroxyapatite, suggesting that the ferrimagnetic glass ceramics were bioactive and could bond to living tissues in physiological environment.
Ferrimagnetic Glass-Ceramics for Magnetic Induction Hyperthermia
Ceramic Transactions Series, 2012
Ferrimagnetic glass-ceramics are potential candidates for magnetic induction hyperthermia [1]. The aim of this work is the preparation and characterization of innovative bioactive ferrimagnetic glass-ceramics in the system SiO 2-Na 2 O-CaO-P 2 O 5-FeO-Fe 2 O 3. These biomaterials contain different amounts of nanometric or sub-micrometric magnetite crystals, homogeneously distributed in an amorphous matrix. They show bioactivity properties, making them also suitable for bone substitutions. The influence of the chemical composition and processing condition (temperature, time, atmosphere) on the glassceramics microstructure and on their properties has been analysed. The specific power loss of these biomaterials varies in the range 20-65 W/g, in function of the glassceramic microstructure. The surface of these materials can be easily modified, in order to bind specific proteins for magnetic drug targeting.
Magnetochemistry
Bioglasses have been used throughout the past century as a biomaterial in the bone regeneration field. However, recent studies have attempted to use them as a therapeutic material as well, mainly in the treatment of osteosarcomas. The most widely recognized bioglass is the 45S5 Bioglass, invented by Larry Hench et al., which presents higher bioactivity. A possible application of this bioglass in the treatment of osteosarcomas can be accomplished by adding specific ions, such as iron, that will allow the use of magnetic hyperthermia and Fenton reaction as therapeutic mechanisms. In this study, a 45S5 Bioglass containing 10%mol of Fe2O3 was produced using the melt-quenching method. A group of samples was prepared by changing the overall ball milling time, from 1 h up to 48 h, to analyze the effects of iron in the bioactive glass matrix and evaluate the influence of particle size on their physical and biological properties. The studied bioglasses showed no evidence of changes in the am...
Ceramics International, 2009
Ferrimagnetic glass-ceramics are promising candidates for magnetic induction hyperthermia, which is one form of inducing deep-regional hyperthermia, by using a magnetic field. The aim of this work was to study the effect of increasing the amount of crystallized magnetite on the magnetic properties of glass-ceramic samples. Two different ferrimagnetic glass-ceramics with the composition based on wollastonite or hardystonite with high quantity ($60%) of magnetite were prepared by melting the starting materials at 1450 8C for 2 h. The influences of chemical composition, amount of crystallized magnetite and microstructure of ferrimagnetic glass-ceramics on magnetic properties of ferromagnetic glassceramics were investigated using differential thermal analysis (DTA), X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM). The X-ray diffraction patterns show the presence of nanometric magnetite crystals in a glassy matrix after cooling from melting temperature. The amount of crystallized magnetite varies as a function of the chemical composition and heat treatment schedule. The presence of ZnO in the glass-ceramics was found to decrease the viscosity and so cases higher degree of mobility of ions leading to higher degree of crystallinity. The higher heat treatment parameters and so the lower viscosity of the glass containing ZnO are assumed to allow the magnetite to grow to larger crystallite size. Glass transition temperature and thermal stability were found to be functions of chemical composition. Magnetic hysteresis cycles were analyzed using a vibrating sample magnetometer (VSM) with a maximum applied field of 15 kOe at room temperature in quasi-static conditions. From the obtained hysteresis loops, the saturation magnetization (Ms), remanance magnetization (Mr) and coercivity (Hc) were determined. The results showed that these materials are expected to be useful in the localised treatment of cancer. #