The sorption study of long lived .sup.94Nb isotope on magnetite was carried out in the pH range of 1-10, both in aerobic and anaerobic conditions. The present study is focused to understand the ...mechanism behind the sorption and to predict the role of magnetite in retarding the migration of the radionuclide. The sorption mechanism and the role of Fe(II) site of magnetite were investigated using solvent extraction, cyclic voltammetry, X-ray photoelectron and absorption spectroscopy. Insignificant difference in the sorption pattern and percentage sorption under aerobic and anaerobic conditions suggests similar sorption mechanism in both conditions. The oxidation states of Nb and Fe of magnetite remained unchanged after sorption process. In acidic medium, the sorption mainly occurs via ion exchange whereas in neutral/basic medium via covalent bond formation of Nb with magnetite.
Herein, we are reporting a facile route to synthesize magnetically separable copper loaded L-DOPA functionalized magnetite nanoparticles (Fe.sub.3O.sub.4-DOPA-CuNPs), which are well characterized by ...FT-IR, PXRD, SEM, EDAX, HRTEM, XPS, TGA and VSM techniques. This single catalyst exhibits excellent catalytic activity towards (i) synthesis of DHPMs via Biginelli reaction (ii) synthesis of imidazoles (iii) synthesis of 2-amino-4H-chromenes (iv) 1,2,3-triazole derivatives by 'Click reaction' under microwave irradiation (MWI). Interestingly it can be easily recovered and reused for subsequent cycles for above mentioned four important multicomponent reactions without any significant decrease in its catalytic activity. Graphical
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We describe a magnetic metal-organic framework for preconcentration of Hg(II). The material is obtained from magnetite (Fe.sub.3O.sub.4) nanoparticles that were modified with ...4-(5)-imidazoledithiocarboxylic acid and then reacted with trimesic acid and Cu(II) acetate to form the metal-organic framework capable of extracting Hg(II). The sorption time, amount of the magnetic nanocomposite, and pH value of the sample were selected as the main affecting factors in sorption, and central composite design and response surface methodology were applied to optimize these parameters. Following sorption of Hg(II), the sorbent is removed by a magnet, Hg(II) is eluted with a solution of thiourea and then quantified by cold vapor AAS. The type, volume and concentration of the eluent, and the elution time were selected for the optimization of the elution. The results showed the sorption process to obey the Langmuir model. The maximum monolayer capacity is as high as 254 mg g.sup.-1, and the Langmuir constant is 0.330 L mg.sup.-1. The findings can be well described by pseudo second-order kinetics. High sorption capacity means that one needs less sorbent. Under the optimal conditions, the limit of detection and limit of quantification for Hg(II) were 10 ng L.sup.-1 and 40 ng L.sup.-1, respectively and the relative standard deviations are <8.3 %. The nanocomposite was successfully applied to the rapid extraction of trace amounts of mercury ions from fish and canned tuna samples.
Magnetite pollution nanoparticles in the human brain Maher, Barbara A.; Ahmed, Imad A. M.; Karloukovski, Vassil ...
Proceedings of the National Academy of Sciences - PNAS,
09/2016, Volume:
113, Issue:
39
Journal Article
Peer reviewed
Open access
Biologically formed nanoparticles of the strongly magnetic mineral, magnetite, were first detected in the human brain over 20 y ago Kirschvink JL, Kobayashi-Kirschvink A, Woodford BJ (1992) Proc Natl ...Acad Sci USA 89(16):7683–7687. Magnetite can have potentially large impacts on the brain due to its unique combination of redox activity, surface charge, and strongly magnetic behavior. We used magnetic analyses and electron microscopy to identify the abundant presence in the brain of magnetite nanoparticles that are consistent with high-temperature formation, suggesting, therefore, an external, not internal, source. Comprising a separate nanoparticle population from the euhedral particles ascribed to endogenous sources, these brain magnetites are often found with other transition metal nanoparticles, and they display rounded crystal morphologies and fused surface textures, reflecting crystallization upon cooling from an initially heated, iron-bearing source material. Such high-temperature magnetite nanospheres are ubiquitous and abundant in airborne particulate matter pollution. They arise as combustion-derived, iron-rich particles, often associated with other transition metal particles, which condense and/or oxidize upon airborne release. Those magnetite pollutant particles which are <∼200 nm in diameter can enter the brain directly via the olfactory bulb. Their presence proves that externally sourced iron-bearing nanoparticles, rather than their soluble compounds, can be transported directly into the brain, where they may pose hazard to human health.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
•Newest advancements related to magnetite.•Microfluidics - smaller reagent volume, waste reduction, fluid mixing precise control.•Overcoming some of the major drawbacks of conventional bulk methods.
...Iron oxide-based nanoparticles have gathered tremendous scientific interest towards their application in a variety of fields. Magnetite has been particularly investigated due to its readily availability, versatility, biocompatibility, biodegradability, and special magnetic properties. As the behavior of nano-scale magnetite is in direct relation to its shape, size, and surface chemistry, accurate control over the nanoparticle synthesis process is essential in obtaining quality products for the intended end uses. Several chemical, physical, and biological methods are found in the literature and implemented in the laboratory or industrial practice. However, non-conventional methods emerged in recent years to bring unprecedented synthesis performances in terms of better-controlled morphologies, sizes, and size distribution. Particularly, microfluidic methods represent a promising technology towards smaller reagent volume use, waste reduction, precise control of fluid mixing, and ease of automation, overcoming some of the major drawbacks of conventional bulk methods. This review aims to present the main properties, applications, and synthesis methods of magnetite, together with the newest advancements in this field.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Iron oxide nanoparticles (IONPs) have been extensively used during the last two decades, either as effective bio-imaging contrast agents or as carriers of biomolecules such as drugs, nucleic acids ...and peptides for controlled delivery to specific organs and tissues. Most of these novel applications require elaborate tuning of the physiochemical and surface properties of the IONPs. As new IONPs designs are envisioned, synergistic consideration of the body's innate biological barriers against the administered nanoparticles and the short and long-term side effects of the IONPs become even more essential. There are several important criteria (
e.g.
size and size-distribution, charge, coating molecules, and plasma protein adsorption) that can be effectively tuned to control the
in vivo
pharmacokinetics and biodistribution of the IONPs. This paper reviews these crucial parameters, in light of biological barriers in the body, and the latest IONPs design strategies used to overcome them. A careful review of the long-term biodistribution and side effects of the IONPs in relation to nanoparticle design is also given. While the discussions presented in this review are specific to IONPs, some of the information can be readily applied to other nanoparticle systems, such as gold, silver, silica, calcium phosphates and various polymers.
This review discusses the physiochemical parameters, hindering translation of iron oxide nanoparticles to clinics, using most recent
in vivo
biodistribution, clearance and toxicity studies.
Magnetite (Fe3O4) nanorods anchored over reduced graphene oxide (rGO) were synthesized through a one-pot synthesis method, where the reduction of GO and in-situ generation of Fe3O4 nanorods occurred ...concurrently. The average head and tail diameter of Fe3O4 nanorods anchored over the rGO matrix are found to be 32 and 11nm, respectively, and morphology, structure and diameter of bare Fe3O4 nanorods were not altered even after the composite formation with rGO. The increased structural disorders and decrement in the sp2 domains stimulated the high electrical conductivity and extended catalytic active sites for the prepared rGO/Fe3O4 nanocomposite. The constructed rGO/Fe3O4/GCE sensor exhibited excellent electrocatalytic activity toward the electrooxidation of dopamine (DA) with a quick response time of 6s, a wide linear range between 0.01 and 100.55µM, high sensitivity of 3.15µAµM−1cm−2 and a lower detection limit of 7nM. Furthermore, the fabricated sensor exhibited a practical applicability in the quantification of DA in urine samples with an excellent recovery rate. The excellent electroanalytical performances and straight-forward, surfactant and template free preparation method construct the rGO/Fe3O4 composite as an extremely promising material for the diagnosis of DA related diseases in biomedical applications.
•Reduction of GO and insitu generation of Fe3O4 nanorods occurred concurrently.•Fe(III)/Fe(II) ion centers involved DA oxidation mechanism has been detailed.•Synergetic interaction between Fe3O4 nanorods and rGO improved DA electroxidation.•rGO/Fe3O4 composite exhibited a faster amperometric response with a LOD of 7nM.•The sensor displayed good analytical reliability in human urine samples.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This study introduces a new type of biocomposite material, which is created by combining Carbon xerogel (CX) which formed from Tannin, as biopolymer, extracted from banana waste, together with ...several metal oxides (Fe3O4, CuO, and MgO). This biocomposite is developed to improve the adsorption of Cobalt (II) by a combination of experimental and theoretical methods. The interaction between the components of the bio composite was confirmed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy. Carbon xerogel/Fe3O4 composite (CX/Fe) material is arranged in a layered structure, with each layer stacked on top of the other. Furthermore, the surface roughness of the CX/Fe material after Co2+ adsorption demonstrated the improved dispersion properties of CX, as well as the weak electrostatic contact between CX and Co2+.Furthermore, thorough examinations were conducted to assess the efficacy of a bio-adsorbent in eliminating cobalt ions from wastewater across different operational circumstances. The findings indicated that carbon xerogels (CX/Fe, CX/Mg, and CX/Cu) exhibited remarkable maximum removal efficiency of around 99.66 %, 98 %, and 97.96 %, respectively, and the adsorption capacity using CX/Fe was 9.994 mg.g-1, CX/Mg was 9.9637 mg.g-1 and CX/Cu was 9.96297 mg.g-1 over a 30-min timeframe. Monte Carlo simulations showed that the examination of molecular structures involving Co2+ on CX/Fe surfaces suggests that chemical forces may have a significant influence on the adsorption process, which is consistent with the experimental findings.
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•Green carbon xerogel with different metal oxides composites for cobalt adsorption.•CX/Fe appeared as fibrous stacked Layered which facilitates the adsorption process.•Gwyddion software confirmed the mechanism of adsorption through Carbon xerogel.•Co2+adsorption on CX/Fe was a chemical reaction verified practical and theoretical.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Recent developments in nanotechnology and application of magnetic nanoparticles, in particular in magnetic iron oxide nanosystems, offer exciting possibilities for nanomedicine. Facile and precise ...synthesis procedures, high magnetic response, tunable morphologies and multiple bio-functionalities of single- and multi-core magnetic particles designed for nanomedicine applications are thoroughly appraised. This review focuses on the structural and magnetic characterization of the cores, the synthesis of single- and multicore iron oxide NPs, especially the design of the latter, as well as their protection, stabilization and functionalization by desired coating in order to protect against the corrosion of core, to prevent non-specific protein adsorption and particle aggregation in biological media, and to provide binding sites for targeting and therapeutic agents.
•Synthesis procedures of iron oxide nanoparticle systems are comparatively analyzed.•The properties of single core and multicore iron oxide nanoparticles are reviewed.•Biocompatible functional coatings are thoroughly discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Nanoparticles have belonged to various fields of biomedical research for quite some time. A promising site-directed application in the field of nanomedicine is drug targeting using magnetic ...nanoparticles which are directed at the target tissue by means of an external magnetic field. Materials most commonly used for magnetic drug delivery contain metal or metal oxide nanoparticles, such as superparamagnetic iron oxide nanoparticles (SPIONs). SPIONs consist of an iron oxide core, often coated with organic materials such as fatty acids, polysaccharides or polymers to improve colloidal stability and to prevent separation into particles and carrier medium 1. In general, magnetite and maghemite particles are those most commonly used in medicine and are, as a rule, well-tolerated. The magnetic properties of SPIONs allow the remote control of their accumulation by means of an external magnetic field. Conjugation of SPIONs with drugs, in combination with an external magnetic field to target the nanoparticles (so-called “magnetic drug targeting”, MDT), has additionally emerged as a promising strategy of drug delivery. Magnetic nanoparticle-based drug delivery is a sophisticated overall concept and a multitude of magnetic delivery vehicles have been developed. Targeting mechanism–exploiting, tumor-specific attributes are becoming more and more sophisticated. The same is true for controlled-release strategies for the diseased site. As it is nearly impossible to record every magnetic nanoparticle system developed so far, this review summarizes interesting approaches which have recently emerged in the field of targeted drug delivery for cancer therapy based on magnetic nanoparticles.
•Presentation of various magnetic drug delivery systems.•Magnetic nano drug carriers: particles, gels, bubbles, capsules, spheres and tubes.•The tumor specific attributes induce various tumor targeting strategies.•Drug release is triggered by pH, temperature, redox or electrical properties.•Clinical translation is the current need for nano drug delivery developments.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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