Functional Magnetic Particles for Medical Application.

Shinkai, Masashige

doi:10.1263/jbb.94.606

Cited by 286 publications

(116 citation statements)

References 48 publications

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“…4 Among the iron oxides, magnetite (Fe 3 O 4 ) is a very promising candidate for biological applications for its biocompatibility 5 and suitable magnetic properties. 6 Biomedical applications also require that iron oxide nanoparticles should be discrete and superparamagnetic with uniformly small particle sizes distribution. [7][8][9] Reported methods for the synthesis of magnetite nanoparticles include reduction of hematite with CO/CO 2 10 or H 2 ; 11 co-precipitation from the solution of ferrous/ferric mixed salt solution in alkaline medium followed by aging and digestion in the temperature range of 90-150 °C; 12 microwave hydrothermal 13 and electrical discharge.…”

Section: Introductionmentioning

confidence: 99%

pH effect on the synthesis of magnetite nanoparticles by the chemical reduction-precipitation method

Andrade¹,

Souza²,

Pereira³

et al. 2010

Quím. Nova

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Recebido em 15/1/09; aceito em 9/9/09; publicado na web em 22/2/10This work aimed at putting in evidence the influence of the pH on the chemical nature and properties of the synthesized magnetic nanocomposites. Saturation magnetization measurements evidenced a marked difference of the magnetic behavior of samples, depending on the final pH of the solution after reaction. Magnetite and maghemite in different proportions were the main magnetic iron oxides actually identified. Synthesis with final pH between 9.7-10.6 produced nearly pure magnetite with little or no other associated iron oxide. Under other synthetic conditions, goethite also appears in proportions that depended upon the pH of the synthesis medium.Keywords: magnetic nano-composites; magnetite; Mössbauer spectroscopy. INTRODUCTIONNanotechnology is a field of growing interest for many physicists and chemists, because the reduced dimension of the solid system leads to peculiar physical and chemical properties that differ from the corresponding bulk materials. The origin of these distinguished properties is either the large surface-to-volume ratio in the particles or the quantum-mechanical nature of electronic structure, which imposes size-dependent modulations or modifications on the chemical behavior, when the size of the particles reaches dimensions of the wavelength of valence electrons in the solid. 1A main driving force for nanoparticle research is the large potential on technological applications. In the case of magnetic nanostructures, applications include data storage technology, 2 medical diagnostics as contrast enhancers in magnetic resonance imaging 3 and drug deliverer. 4 Among the iron oxides, magnetite (Fe 3 O 4 ) is a very promising candidate for biological applications for its biocompatibility 5 and suitable magnetic properties.6 Biomedical applications also require that iron oxide nanoparticles should be discrete and superparamagnetic with uniformly small particle sizes distribution. 7-9Reported methods for the synthesis of magnetite nanoparticles include reduction of hematite with CO/CO 2 10 or H 2 ; 11 co-precipitation from the solution of ferrous/ferric mixed salt solution in alkaline medium followed by aging and digestion in the temperature range of 90-150 °C; 12 microwave hydrothermal 13 and electrical discharge. 14 Qu et al. 15 reported a method for the direct preparation of spherically-shaped magnetite nanoparticles smaller than 10 nm, from aqueous solution of a ferric salt, which is stable in air. In such a method, the ferrous ions are formed by partial reduction of ferric ions with Na 2 SO 3 before the precipitation agent is added.In this work, it was studied the influence of the pH , on the chemical nature and properties of magnetic nanocomposites, prepared by precipitation from partially reduced ferric chloride aqueous solutions, via a modified route from that originally proposed by Qu et al.. 15 The chemical and magnetic properties of the formed nanomaterials were investigated in detail. EXPERIMENTAL MaterialsFerric chloride...

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Section: Introductionmentioning

confidence: 99%

pH effect on the synthesis of magnetite nanoparticles by the chemical reduction-precipitation method

Andrade¹,

Souza²,

Pereira³

et al. 2010

Quím. Nova

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“…2 The prepared suspensions of coated magnetic nanoparticles have recently been the focus of intensive research not only for the study of the physics of magnetism in the nanometer scale, 3 but also for the use of ferrofluids in many technological and biomedical applications such as technical heating processes, media contrast agents in magnetic resonance imaging ͑MRI͒, and as therapeutic agents for RF-magnetic hyperthermia. [4][5][6][7][8][9][10][11][12][13] Specifically, MRI contrast agents are chemical substances introduced to the anatomical or functional region being imaged, in order to increase the differences between different tissues or between normal and abnormal tissue, by altering the relaxation times. MRI contrast agents are classified according to the different changes in relaxation times after their injection.…”

Section: Introductionmentioning

confidence: 99%

In vitro studies on ultrasmall superparamagnetic iron oxide nanoparticles coated with gummic acid for T2 MRI contrast agent

et al. 2007

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Ultrasmall superparamagnetic iron oxide nanoparticles coated with gummic acid have been investigated as possible constituents of aqueous ferrofluids for biomedical applications and especially for MRI contrast agent. The structural characteristics and the size of the nanoparticles have been analyzed as well as the magnetic properties. In order to evaluate any possible capabilities as a contrast agent, the relaxation time, T2, of hydrogen protons in the colloidal solutions of nanoparticles have been measured in order to gain information on the relaxation behavior compared to other MRI contrast agents. The in vitro cytotoxicity of the obtained magnetic nanoparticles of iron oxide coated with gummic acid was investigated by two separate methods ͑MTT and FACS analysis͒ and by using three different normal and transformed cell lines. Our results showed that the synthesized nanoparticles had no toxic effect on any of the cell lines used.

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“…She was a Doctor course student of Kyushu University (no photograph). our group tried to apply magnetic microbeads 13,14 for easy trapping of microbeads for the immunoreaction. In addition, we decided to use chemiluminescence determination for improving the detection limit of the immunoassay system.…”

Section: ·2 Chemiluminescence Determinationmentioning

confidence: 99%