• Medical Lasers
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• v.10 no.1
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• pp.7-14
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• 2021

In cancer therapy, it is often desirable to use precision medicine that involves treatments of high specificity. One such treatment is the use of photo-triggered theranostic nanoparticles. These nanoparticles make it possible to visualize and treat tumors specifically in a controlled manner with a single injection. Several novel and powerful photo-triggered theranostic nanoparticles have been developed. These range from small organic dyes, semiconducting and biopolymers, to inorganic nanomaterials such as iron-oxide or gold nanoparticles, carbon nanotubes, and upconversion nanoparticles. Using photo-triggered theranostic nanoparticles and localized irradiation, complete tumor ablation can be achieved without causing significant toxicity to normal tissue. Given the great advances and promising future of theranostic nanoparticles, this review highlights the progress that has been made in the past couple of years, the current challenges faced and offers a future perspective.

• Applied Chemistry for Engineering
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• v.31 no.1
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• pp.13-18
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• 2020

Iron oxide nanoparticles were microencapsulated using fibroin, a protein polymer of silk fiber, for theragnostic applications. The content of iron oxide was determined to be 4.28% by thermogravimetric analysis and 5.11% by magnetometer. A suspension of murine fibroblast 3T3 cells grown in medium supplemented with iron oxide-microcapsules turned clear in response to the magnetic force and the cells aggregated to the magnet direction. Neodymium magnets placed on the top of the culture dish, and attracted cells to the center of the culture surface. The cells collected on the culture surface aggregated to form a rough spheroid of 2 mm in a diameter after 72 h. In the outer layer of the cell aggregate, cells were relatively large and gathered together to form a dense tissue, but the central part was observed to undergo cell death due to the mass transfer restriction. In the outer layer, iron oxide-microcapsules were lined up like chains in the direction of magnetic force. Using microCT, it was demonstrated that the iron oxides inside the cell aggregate were not evenly distributed but biased to the magnetic direction.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.745-748
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• 1995

Magnetic nanoparticles of iron and iron oxide have been prepared in a modified upward thermal diffusion cloud chamber using pulsed laser evaporation. SEM/TEM studies of these particles reveal a size distribution with a mean diameter of about $60\;{\AA}$. FTIR spectrum measurements are used to investigate the difference in oxidation level between nanoparticles prepared at different partial oxygen pressures. The complex magnetic behaviour of these particles was studied using DC- and AC-susceptibility measurements. All samples exhibit superparamagnetism with blocking temperatures ranging from 50 K to above room temperature. The coercivity fields as well as the dependence of the blocking temperature on measuring frequency have been studied. magnetic anisotropy constants are found to be one order of magnitude higher than is known for the bulk values. The mean particle size estimated from the magnetic data is found to be in perfect agreement with the TEM observations.

• Korean Journal of Radiology
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• v.22 no.10
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• pp.1708-1718
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• 2021

Objective: The purpose of this study was to evaluate the magnetic resonance (MR) characteristics and applicability of new, uniform, extremely small iron-based nanoparticles (ESIONs) with 3-4-nm iron cores using contrast-enhanced magnetic resonance angiography (MRA). Materials and Methods: Seven types of ESIONs were used in phantom and animal experiments with 1.5T, 3T, and 4.7T scanners. The MR characteristics of the ESIONs were evaluated via phantom experiments. With the ESIONs selected by the phantom experiments, animal experiments were performed on eight rabbits. In the animal experiments, the in vivo kinetics and enhancement effect of the ESIONs were evaluated using half-diluted and non-diluted ESIONs. The between-group differences were assessed using a linear mixed model. A commercially available gadolinium-based contrast agent (GBCA) was used as a control. Results: All ESIONs showed a good T1 shortening effect and were applicable for MRA at 1.5T and 3T. The relaxivity ratio of the ESIONs increased with increasing magnetic field strength. In the animal experiments, the ESIONs showed peak signal intensity on the first-pass images and persistent vascular enhancement until 90 minutes. On the 1-week follow-up images, the ESIONs were nearly washed out from the vascular structures and organs. The peak signal intensity on the first-pass images showed no significant difference between the non-diluted ESIONs with 3-mm iron cores and GBCA (p = 1.000). On the 10-minutes post-contrast images, the non-diluted ESIONs showed a significantly higher signal intensity than did the GBCA (p < 0.001). Conclusion: In the phantom experiments, the ESIONs with 3-4-nm iron oxide cores showed a good T1 shortening effect at 1.5T and 3T. In the animal experiments, the ESIONs with 3-nm iron cores showed comparable enhancement on the first-pass images and superior enhancement effect on the delayed images compared to the commercially available GBCA at 3T.

• KSBB Journal
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• v.27 no.3
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• pp.157-160
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• 2012

When iron oxide magnetic nanoparticles were synthesized by co-precipitation method using aqueous ammonia as reducing agent, the synthesized particles were aggregated and thus precipitation occurred. Using Magnolia kobus leaf extract as reducing agent, spherical nanoparticles of 50~200 nm were synthesized with low yield. By using both Magnolia kobus leaf extract and aqueous ammonia as reducing and stabilizing agents, smaller nanoparticles of 40~120 nm could be synthesized with various shapes. The synthesized magnetic nanoparticles were characterized with field emission transmission electron microscopy (FE-TEM) and scanning electron microscopy (SEM). TEM and SEM images showed that the magnetic nanoparticles are a mixture of triangles, tetragons, rods and spherical structures.

• Investigative Magnetic Resonance Imaging
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• v.16 no.1
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• pp.31-39
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• 2012

Purpose : To determine the optimal combination of commercially available superparamagnetic iron oxide (SPIO) nanoparticles with transfection agents (TA). Materials and Methods: Protamine sulfate (Pro) and poly-L-lysin (PLL) were incubated with ferumoxide and ferucarbotran in human mesenchymal stem cells at various concentrations, and cellular viability were evaluated. Cellular iron uptake was qualitatively and quantitatively evaluated. Cell visibility was assessed via MR imaging and the T2-relaxation time was calculated. Results: The cellular viabilities with ferucarbotran were more significantly decreased than those with ferumoxide (p < 0.05). Iron uptake with ferumoxide was significantly higher than that for those with with ferucarbotran. The T2-relaxation time was observed to be shorter with ferumoxide in comparison to those with ferucarbotran (p < 0.05). Ferumoxide at a concentration of 25 ${\mu}g$/ml in combination with either Pro or PLL at a concentration of 3.0 ${\mu}g$/ml did not adversely impact cell viability, maximized iron uptake, and exhibited a lower T2-relaxation time in comparison to other combinations. Conclusion: Stem cells with ferumoxide exhibited a higher cellular viability and iron uptake in comparison to ferucarbotran-treated stem cells. A 25 ${\mu}g$/ml of ferumoxide with a 3.0 ${\mu}g$/ml of TA is sufficient to label mesenchymal stem cells.

• Journal of Biomedical Engineering Research
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• v.38 no.3
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• pp.102-110
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• 2017

Cancer is one of the most challenging human diseases. Current clinical methods have limitations for early-stage cancer diagnosis and effective therapy. Moreover, current surgical methods to remove tumors are not precise enough and chemotherapy destroys normal tissues as well as malignant tumors, resulting in severe side effects such as hair loss, vomiting, diarrhea, and blood disorders. Recently, nanotechnology using nano-sized particles suggests advanced solutions to overcome the limitations. Various nanoparticles have been reported for more accurate diagnosis and minimized side effects. However, current nanoparticles still show limited targeting accuracy for cancer generally below 5% injection dosage. Therefore, herein we report a new nanoparticle inducing device(NID) to guide the nanoparticles externally by using both variable magnetic fields and blood flows. NID can be a promising approach to improve targeting accuracy for drug delivery using iron oxide nanoparticles.

• Bulletin of the Korean Chemical Society
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• v.35 no.4
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• pp.1233-1236
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• 2014

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.195.2-195.2
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• 2007

• Proceedings of the Korean Magnestics Society Conference
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• 2004.06a
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• pp.126-127
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• 2004