• 한국자기학회지
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• 제22권1호
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• pp.11-14
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• 2012

Expanded graphite 산화물과 자성 나노입자의 복합화는 화학적 방법을 이용하였으며, Ni과 Co 나노입자를 사용하여 간단한 방법으로 자기적 특성을 가지는 graphite 산화물을 합성하였다. $H_2SO_4$에 $(NH_4)SO_4$을 첨가한 혼합 용액을 제조하여, natural graphite와 반응시키고, 1차 열처리하여 expanded graphite를 제조하였다. $1050^{\circ}C$에서 30초간 급속 2차 열처리와 화학적 산화 과정을 거쳐 expanded graphite oxide로 변화시킨 뒤에 $Ni(acac)_2$, $Co(acac)_3$과 화학적 반응을 통하여 Expanded graphite 산화물자성 나노입자 복합체를 제조하였다. 결정 구조 분석을 위하여 x-선 회절 측정을 수행하였으며, Raman 분광 측정으로 graphite 산화물의 층상 구조를 분석하였다. 미세구조 분석을 위하여 투과전자현미경 측정을 수행하였으며, 진동시료형 자화율측정기를 이용하여 복합체의 자기적 특성을 연구하였다. 이러한 연구 결과는 graphite 화합물과 자성 물질의 복합화를 위한 기저 기술로 활용될 수 있을 것이다.

• Bulletin of the Korean Chemical Society
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• 제30권8호
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• pp.1855-1857
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• 2009

• 대한방사성의약품학회지
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• 제4권1호
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• pp.36-42
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• 2018

Molecular imaging refers to detect the biochemical process in living organisms at the cellular and molecular levels and to quantify them. Due to several advantages of nanomaterials, various molecular images using nanomaterials are being tried. Attempts have been made to combine nanoparticles, known as micro- or nanosized nanomaterials, with radioactive isotopes for molecular imaging probe. The radiolabeled nanoparticles will expend the molecular imaging due to nanoparticle's size-dependent nature. In particular, iron oxide nanoparticles can be used for magnetic resonance imaging, can be adjusted in size, easily functionalized, and biocompatible, making it a very good platform for molecular imaging. In addition, iron oxide nanoparticles may be the best example for a new approach to molecular imaging techniques. In this paper, we introduce various methods for preparation of iron oxide nanoparticle combined with radioisotope starting from various synthesis methods of iron oxide nanoparticles to utilize iron oxide nanoparticles as a platform for molecular imaging through radioactive labeling.

• 전자공학회논문지SC
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• 제48권6호
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• pp.51-56
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• 2011

자성 산화철 나노입자(iron oxide nanoparticle, ${\gamma}-Fe_2O_3$) 표면을 기능성 유기 분자를 이용하여 아민기($-NH_2$), 카르복실기(-COOH)로 표면 처리 하였으며, 이들 기능기로 표면 처리된 산화철 나노입자를 FT-IR을 이용하여 나노입자 표면을 분석하였다. 아민기, 카르복실기로 표면처리된 산화철 나노입자 표면에 특정 배열을 갖는 21-base pair 길이의 프로브 DNA를 고정하였고, 형광 라벨(Cy5)이 부착된 상보적, 비상보적 타게트 DNA를 이용하여 고정된 프로브 DNA와 hybridization을 진행하였다. 각각의 상보적, 비상보적 타게트 DNA와 hybridization 처리한 산화철 나노입자를 confocal microscopy를 이용하여 관찰하였으며, 그 결과 산화철 나노입자를 이용하여 특정 배열의 DNA검출에 성공하였다.

• Journal of the Optical Society of Korea
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• 제10권3호
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• pp.99-104
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• 2006

We introduce a novel contrast mechanism for imaging superparamagnetic iron oxide (SPIO) nanoparticles (average diameter ${\sim}100nm$) using magneto-motive optical Doppler tomography (MM-ODT), which combines an externally applied temporally oscillating high-strength magnetic field with ODT to detect the nanoparticles flowing through a glass capillary tube. A solenoid cone-shaped ferrite core extensively increased the magnetic field strength ($B_{max}=1\;T,\;{\Delta}|B|^2=220T^2/m$) at the tip of the core and also focused the magnetic force on targeted samples. Nanoparticle contrast was demonstrated in a capillary tube filled with the SPIO solution by imaging the Doppler frequency shift which was observed independent of the flow rate and direction. Results suggest that MM-ODT may be a promising technique to enhance SPIO nanoparticle contrast for imaging fluid flow.

• 한국세라믹학회지
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• 제45권10호
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• pp.605-609
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• 2008

This work describes the preparation of functionalized magnetic nanoparticles(MNPs) and their bioapplication to human DNA separation. Silica coated MNPs were prepared by changing the volume ratio of tetraethyl orthosilicate(TEOS) for controlled coating thickness on the original nanoparticle of MNPs. The sol-gel process in silica coating on MNPs surface was adapted for relatively mild reaction condition, low-cost, and surfactant-free. And then amino functionalized magnetic nanoparticles were synthesized using amine groups as surface modifiers. The result of adsorption efficiency for human DNA with amino-functionalized silica coated MNPs was calculated as a function of the number of amine groups.

• 한국연소학회지
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• 제16권2호
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• pp.33-39
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• 2011

We demonstrated heat generation efficiency of the magnetic hyperthermia system to find optimal condition using gelatin tissue phantom. Magnetic hyperthermia induction can be used to make heat generation with different concentration of $Fe_3O_4$ iron oxide inside tissue phantom and magnetically labeled cells by applying AC magntic field at a frequency of 145 kHz. It was observed that the maximum temperature achieved in the magnetic gelatin tissue phantom increased with the concentration of $Fe_3O_4$ iron oxide and alternating magnetic field intensity. Results were discussed with respect to further optimization of therapeutic technique for biomedical application with modified functional nanoparticles.

• 대한의용생체공학회:의공학회지
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• 제38권3호
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• pp.102-110
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• 2017

본 논문은 자석을 회전시켜 실시간으로 자기장을 변화시키고 그로 인해 특정 조건에서 산화철 나노입자를 side point(피부)보다 center point(심부)에서 더 많이 유도할 수 있다는 가능성을 제시하였다. 향후 연구로 유속에 따른 Critical Magnetic flux density, 시간에 따른 나노입자 축적량, 자기장과 산화철 나노입자의 상호작용을 고려한 실험 설계, 전자석 등을 이용한 자기장조절을 연구하여 실질적인 혈관에서 본 실험을 진행할 계획이다.

• 한국분말재료학회지
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• 제11권1호
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• pp.16-21
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• 2004

The nano-sized Co particles were successfully synthesized by chemical vapor condensation (CVC) process using the precursor of cobalt carbonyl ($Co_2(CO)_8$). The influence of carrier gases on the microstructure and magnetic properties of nanoparticles was investigated by means of XRD, TEM, XPS and VSM. The Co nano-particles with different phases and shapes were synthesized with a change of carrier gas : long string morphologies with coexistence of fcc and hcp structure in Ar carrier gas condition; finer Co core in a mass of cobalt oxide with only fcc structure in He; rod type cobalt oxide phase in Ar＋6vol％$O_2$. The saturation magnetization and coercivity was lower in Co nanoparticles synthesized in He carrier gas, due to their finer size.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.1-1
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• 2011

We developed a new generalized synthetic procedure, called as "heat-up process," to produce uniform-sized nanocrystals of many transition metals and oxides without a size selection process. We were able to synthesize uniform magnetite nanocrystals as much as 1 kilogram-scale from the thermolysis of Fe-oleate complex. Clever combination of different nanoscale materials will lead to the development of multifunctional nano-biomedical platforms for simultaneous targeted delivery, fast diagnosis, and efficient therapy. In this presentation, I would like to present some of our group's recent results on the designed fabrication of multifunctional nanostructured materials based on uniform-sized magnetite nanoparticles and their medical applications. Uniform ultrasmall iron oxide nanoparticles of <3 nm were synthesized by thermal decomposition of iron-oleate complex in the presence of oleyl alcohol. These ultrasmall iron oxide nanoparticles exhibited good T1 contrast effect. In in vivo T1 weighted blood pool magnetic resonance imaging (MRI), iron oxide nanoparticles showed longer circulation time than commercial gadolinium complex, enabling high resolution imaging. We used 80 nm-sized ferrimagnetic iron oxide nanocrystals for T2 MRI contrast agent for tracking transplanted pancreatic islet cells and single-cell MR imaging. We reported on the fabrication of monodisperse magnetite nanoparticles immobilized with uniform pore-sized mesoporous silica spheres for simultaneous MRI, fluorescence imaging, and drug delivery. We synthesized hollow magnetite nanocapsules and used them for both the MRI contrast agent and magnetic guided drug delivery vehicle.