• Polymer(Korea)
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• v.36 no.5
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• pp.586-592
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• 2012

Iron oxides ($Fe_3O_4$) are metabolically secreted after endocytosed by cells, indicating no cytotoxicity. Therefore, they are widely used as a contrast agent before photographing of magnetic resonance imaging. In this study, iron oxide nanoparticles are synthesized by the co-precipitation method and subsequently immobilized with a homing peptide (AP), which specifically interacts with interleukin-4 receptor located on the membrane of endothelial and bladder cancer cells. The size of AP-immobilized iron oxide particle is about 39 nm. Intracellular uptake of the AP-immobilized iron oxide nanoparticles was investigated using bladder cancer cells and fibroblasts as the control. As the result, the nanoparticles are specificially uptaken by bladder cancer cells. However, the nanoparticles are not specificially uptaken by fibroblast. It could be said that the AP-immobilized iron oxide nanoparticles have a potential to be used as a contrast agent for early diagnosis of cancer.

• Journal of the Korean Ceramic Society
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• v.55 no.3
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• pp.230-238
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• 2018

Superparamagnetic iron oxide nanoparticles (SPIONs) have been prepared without using surfactants to assess their stability at different time intervals. The synthesized particles were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, ultraviolet-visible-near infrared spectroscopy, and energy dispersive spectroscopy. Field emission scanning electron microscopy and high-resolution transmission electron microscopy images of the samples were also investigated. The average particle size was measured to be 12.7 nm even in the polydispersed form. The magnetic and dielectric characteristics of the $Fe_3O_4$ nanoparticles have also been studied and discussed in detail.

• Journal of Powder Materials
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• v.11 no.1
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• pp.50-54
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• 2004

Nanoparticles of iron oxides have been prepared by the levitational gas condensation (LGC) method, and their structural and magnetic properties were studied by XRD, TEM and Mossbauer spectroscopy. Fe clusters were evaporated from a surface of the levitated liquid Fe droplet and then condensed into nanoparticles of iron oxide with particle size of 14 to 30 nm in a chamber filled with mixtures of Ar and $O_2$ gases. It was found that the phase transition from both $\gamma$-$Fe_2O_3$ and $\alpha$-Fe to $Fe_3O_4$, which was evaluated from the results of Mossbauer spectra, strongly depended on the $O_2$ flow rate. As a result, $\gamma$-$Fe_2O_3$ was synthesized under the $O_2$ flow rate of 0.1$\leq$$Vo_2$(Vmin)$\leq$0.15, whereas $Fe_3O_4$ was synthesized under the $O_2$, flow rate of 0.15$\leq$$Vo_2$(Vmin)$\leq$0.2.

• Advances in nano research
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• v.6 no.1
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• pp.1-19
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• 2018

Iron oxide nanoparticles excite researcher interest in biomedical applications due to their low cost, biocompatibility and superparamagnetism properties. Magnetic iron oxide especially magnetite ($Fe_3O_4$) possessed a superparamagnetic behaviour at certain nanosize which beneficial for drug and gene delivery, diagnosis and imaging. The properties of nanoparticles mainly depend on their synthesis procedure. There has been a massive effort in developing the best synthetic strategies to yield appropriate physico-chemical properties namely co-precipitation, thermal decomposition, microemulsions, hydrothermal and sol-gel. In this review, it is discovered that magnetite nanoparticles are best yielded by co-precipitation method owing to their simplicity and large production. However, its magnetic saturation is within range of 70-80 emu/g which is lower than thermal decomposition and hydrothermal methods (80-90 emu/g) at 100 nm. Dimension wise, less than 100 nm is produced by co-precipitation method at $70^{\circ}C-80^{\circ}C$ while thermal decomposition and hydrothermal methods could produce less than 50 nm but at very high temperature ranging between $200^{\circ}C$ and $300^{\circ}C$. Thus, co-precipitation is the optimum method for pre-compliance magnetite nanoparticles preparation (e.g., 100 nm is fit enough for biomedical applications) since thermal decomposition and hydrothermal required more sophisticated facilities.

• Journal of the Korean Magnetics Society
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• v.26 no.1
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• pp.13-18
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• 2016

The ac magnetic susceptibility was measured in iron-oxide nanoparticles with average size of 26 nm, which were uniformly dispersed in organic solvent. The ac magnetic susceptibility measured under zero magnetic fields was well fitted with Debye relaxation model and the relaxation frequency was 370 Hz. The relaxation frequency of the nanoparticles coincided with relaxation time of the Brownian motion, which is due to the viscosity of the liquid medium in which magnetic nanoparticles dwell. The Brown relaxation frequencies were linearly increased with magnetic field.

• Journal of Powder Materials
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• v.18 no.4
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• pp.347-358
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• 2011

Two different schemes were adopted to fabricate ordered macroporous structures with face centered cubic lattice of air spheres. Monodisperse polymeric latex suspension, which was synthesized by emulsifier-free emulsion polymerization, was mixed with metal oxide ceramic nanoparticles, followed by evaporation-induced self-assembly of the mixed hetero-colloidal particles. After calcination, inverse opal was generated during burning out the organic nanospheres. Inverse opals made of silica or iron oxide were fabricated according to this procedure. Other approach, which utilizes ceramic precursors instead of nanoparticles was adopted successfully to prepare ordered macroporous structure of titania with skeleton structures as well as lithium niobate inverted structures. Similarly, two different schemes were utilized to obtain disordered macroporous structures with random arrays of macropores. Disordered macroporous structure made of indium tin oxide (ITO) was obtained by fabricating colloidal glass of polystyrene microspheres with low monodispersity and subsequent infiltration of the ITO nanoparticles followed by heat treatment at high temperature for burning out the organic microspheres. Similar random structure of titania was also fabricated by mixing polystyrene building block particles with titania nanoparticles having large particle size followed by the calcinations of the samples.

• Journal of Biosystems Engineering
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• v.42 no.4
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• pp.323-329
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• 2017

Purpose: Biocompatible capsules have recently been highlighted as a novel platform for delivering various components, such as drug, food, and agriculture pesticides, to overcome the current limitations of living systems, such as those in agriculture, biology, the environment, and foods. However, few active targeting systems using biocompatible capsules and physical forces simultaneously have been developed in the agricultural engineering field. Methods: Here, we developed an active targeting delivery platform that uses biocompatible alginate capsules and controls movements by magnetic forces for agricultural and biological engineering applications. We designed and fabricated large-scale biocompatible capsules, using custom-made nozzles ejecting alginate solutions for encapsulation. Results: To develop the active target delivery platforms, we incorporated iron oxide nanoparticles in the large-scale alginate capsules. The sizes of alginate capsules were controlled by regulating the working conditions, such as concentrations of alginate solutions and iron oxide nanoparticles. Conclusions: We confirmed that the iron oxide particle-incorporated large-scale alginate capsules moved actively in response to magnetic fields, which will be a good strategy for active targeted delivery platforms for agriculture and biological engineering applications, such as for the controlled delivery of agriculture pesticides and biocontrol agents.

• Journal of the Optical Society of Korea
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• v.11 no.1
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• pp.26-33
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• 2007

We demonstrate the capability of differential-phase optical coherence tomography (DP-OCT) to detect superparamagnetic iron oxide (SPIO) nanoparticles taken up by liver parenchymeal macrophages (Kupffer cells). We apply an external time-varying high-intensity focused magnetic field. Our experiments demonstrate a novel diagnostic modality to detect macrophages that have taken up SPIO nanoparticles. Magnetic force acting on the nanoparticles was varied by applying a sinusoidal current to a solenoid containing a conical iron core that substantially increased and focused the magnetic field strength ($B_{max}$ = 2 Tesla). $ApoE^{-/-}$ mice were sacrificed 2 days post intravenous injections of different SPIO doses (1.0, and 0.1 mmol Fe/kg body weight). Livers of $ApoE^{-/-}$ mice with and without injection of SPIO nanoparticles were investigated using DP-OCT, which detects tissue movement with nanometer resolution. Frequency response of iron-laden liver movement was twice the stimulus frequency. Movement was not observed in livers of control mice. Results of our experiments indicate DP-OCT is a candidate methodology to detect tissue based macrophages containing SPIO nanoparticles excited by an external focused magnetic field.

• Polymer(Korea)
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• v.28 no.2
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• pp.170-176
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• 2004

The effect of reaction conditions on the size and size distribution of superparamagnetic iron oxide coated with siloxane was big investigated by using dynamic light scattering. The hydrogen bond between the hydroxyl groups on tile surface of the magnetite and silanol was confirmed by FT-IR. The size of nanoparticles increased with the reaction temperature, but decreased with monomer contents and agitation speeds. There was not a big difference in size of nanoparticles, prepared by different reaction conditions, but its distribution was in the range of 14∼41nm. All samples exhibited the superparamagnetic nature. The magnetic susceptibility of the nanoparticles increased with the reaction temperature while it decreased with the monomer content and agitation speed.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2279-2282
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• 2007

Highly crystalline, uniform Fe nanoparticles were successfully synthesized and encapsulated in zirconia shell using sol-gel process. Two different approaches have been employed for the coating of Fe nanoparticle with zirconia. The thickness of zirconia shell can be readily controlled by altering molar ratio of Fe nanoparticle core to zirconia precursor in the first case where as reaction time was found to be most effective parameter to controlled the shell thickness in the second method. The structure and magnetic properties of the ZrO2-coated Fe nanoparticles were studied. TEM and HRTEM images show a typical core/shell structure in which spherical α-iron crystal sized of ~25 nm is surrounded by amorphous ZrO2 coating layer. TGA study showed an evidence of weight loss of less than 2% over the temperature range of 50-500 °C. The nanoparticles are basically in ferromagnetic state and their magnetic properties depend strongly on annealing temperature. The thermal treatment carried out in as-prepared sample resulted in reduction of coercivity and an increase in saturation magnetization. X-ray diffraction experiments on the samples after annealing at 400-600 °C indicate that the size of the Fe@ZrO2 particles is increased slightly with increasing annealing temperature, indicating the ZrO2 coating layer is effective to interrupt growing of iron particle according to heat treatment.