• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
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• pp.501-519
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• 2003

Silk Sericin(SS) is a natural protein extracted from cocoon of bombix mori and shows moisturizing effect to the skin due to a number of hydroxyl groups in the structure. But its application to cosmetics is limited due to its poor solubility in water. In order to solve this drawback and expand its application to cosmetics, polyethyleneglycol(PEG) was conjugated with sericin by reacting activated polyethyleneglycol(ActPEG). Reaction site of sericin is tyrosine residue, which was determined by using $^1$H-NMR. Random coil structure of sericin was transformed to beta-sheet structure by conjugating polyethyleneglycol. It was confirmed that melting point of sericin-PEG conjugate was lowered compared to that of each sericin and PEG due to the interaction between sericin and PEG in crystalline structure. Self-assembled sericin-PEG nanoparticle was obtained by dialyzing with alcohol solution of sericin-PEG conjugate against water. The particle is spherical and has 200-400nm of size. The moisturizing ability of sericin-PEG nanoparticle was much higher than that of sericin itself. Incorporation of vitamin A into sericin-PEG nanoparticle was carried out by diafiltration method. The content of incorporated Vitamin A in sericin-PEG nanoparticle was 8.9 wt％. Releasing behaviour of vitamin A incorporated into nanoparticle was tested in phosphate buffer, pH 7.4 at 37$^{\circ}C$. and half-life of Vitamin A release was 43hrs. Sericin-PEG nanoparticle exhibited higher moisturing effect than sericin itself and distilled water, respectively. No toxicity and irritation were observed in animal tests. It can be expected that the self-assembled sericin-PEG nanoparticle can be developed for cosmetics.

• Carbon letters
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• 제10권4호
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• pp.325-328
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• 2009

This cycloaddition of [70]fullerene with methyl azidoacetate in benzene under ultrasonic irradiated condition afforded the closed [5,6]-bridged aziridino[70]fullerene derivative, which was unusual product of cycloaddition to the 5,6-junction of fullerene. Its structure was determined by FAB-MS, UV-vis, $^1H-$ and $^{13}C$-NMR spectral data. The closed [5,6]-bridged aziridino[70]fullerene-functionalized gold nanoparticle films were self-assembled using the layer-by-layer method on the reactive of glass slides functionalized with 3-mercaptopropyl trimethoxysilane. The functionalized glass slides were alternately soaked in the solution containing closed the [5,6]-bridged aziridino[70]fullerene and 4-aminothiophenoxide/hexanethiolate-protected gold nanoparticles. The closed [5,6]-bridged aziridino[70]fullerene-functionalized gold nanoparticle films have grown up to 5 layers depending on the immersion time. The self-assembled nanoparticle multilayer films were characterized using UV-vis spectroscopy showed that the surface plasmon band of gold at 527 nm gradually became more evident as successive layers were added to the films.

• Bulletin of the Korean Chemical Society
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• 제25권11호
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• pp.1681-1686
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• 2004

Self-assembled systems with polyamidoamine (PAMAM) dendrimers combined with gold nanoparticles have been widely studied because of their potential applications in molecular electronics, catalyst carriers, chemical sensors, and biomedical devices. In our work, gold nanoparticle monolayers and multilayers with pure and ferrocene-tethered PAMAM dendrimers as cross-linking molecules were deposited on a mixed self-assembled monolayer of gold substrates. The various generations of PAMAM dendrimers can be covalently attached to mercaptoundecanoic acid mixed with a mercaptoundecanol self-assembled monolayer. Cyclic voltammograms show that redox peak currents on the alternate multilayers of gold nanoparticles and ferrocene-tethered PAMAM dendrimers increase as the number of layers increases. Fourier transform IR external reflection spectroscopy and scanning electron microscopy support the results from electrochemical measurements.

• Elastomers and Composites
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• 제43권4호
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• pp.264-270
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• 2008

3-아미노프로필메톡시 실란을 처리한 반응성 있는 유리표면 위에 "LbL" 방법을 사용하여 $\alpha$-D-만노실 풀러렌[$C_{60}$]-금 나노입자를 자기조립 하였다. 표면 처리한 유리막을 $\alpha$-D-만노실 풀러렌[$C_{60}$]과 헥산 티올레이트/아미노 티오페녹사이드-금나노입자를 포함하고 있는 용액속에 교대로 담그었다. $\alpha$-D-만노실 풀러렌[$C_{60}$] -금 나노입자 필름을 시간에 따라 다중성(5층)막으로 제조하였다. 자외선-가시광선 분광기를 사용한 자기조립 나노입자 필름의 분석은 530 nm 일 때 금 나노입자의 표면 플라스몬 밴드로 인해 다중성(5층)막이 형성되는 것을 보여주었다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1193-1194
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• 2006

The magnetic ferrite nanoparticles were synthesized and coated by silica precursor in controlling the coating thicknesses and sizeses. The surface modification was performed with amino-functionalized organic silanes on silica coated magnetic nanoparticles. The use of functionalized self-assembled magnetic ferrite nanoparticles for nucleic acid separation process give a lot of advantages rather than the conventional silica based process.

• 한국분말재료학회지
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• 제24권3호
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• pp.229-234
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• 2017

We report on a simple and robust route to the spontaneous assembly of well-ordered magnetic nanoparticle superstructures by irreversible evaporation of a sessile single droplet of a mixture of a ferrofluid (FF) and a nonmagnetic fluid (NF). The resulting assembled superstructures are seen to form well-packed, vertically arranged columns with diameters of $5{\sim}0.7{\mu}m$, interparticle spacings of $9{\sim}2{\mu}m$, and heights of $1.3{\sim}3{\mu}m$ The assembled superstructures are strongly dependent on both the magnitude of magnetic field and the mixing ratio of the mixture. As the magnitude of the externally applied magnetic field and the mixing ratio of the mixture increase gradually, the size and interspacing of the magnetic nanoparticle aggregations decrease. Without an externally applied magnetic field, featureless patterns are observed for the ${\gamma}-Fe_3O_4$ nanoparticle aggregations. The proposed approach may lead to a versatile, cost-effective, fast, and scalable fabrication process based on the field-induced self-assembly of magnetic nanoparticles.

• Bulletin of the Korean Chemical Society
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• 제31권2호
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• pp.291-297
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• 2010

This article introduces a facile nanoparticle self-assembly/annealing method for the preparation of nanoisland films. First, nanoparticle-polymer multilayer films are prepared with layer-by-layer assembly. Nanoparticle multilayer films are then annealed at $~500^{\circ}C$ in air to evaporate organic matters from the films. During the annealing process, the nanoparticles on the solid surface undergo nucleation and coalescence, resulting in the formation of nanostructured gold island arrays. By controlling the overall thickness (number of layers) of nanoparticle multilayer films, nanoisland films with various island density and different average sizes are obtained. The surface property of gold nanoisland films is further controlled by the self-assembly of alkanethiols, which results in an increased surface hydrophobicity of the films. The structure and characteristics of these nanoisland film arrays are found to be quite comparable to those of nanoisland films prepared by vacuum evaporation method. However, this self-assembly/annealing protocol is simple and requires only common laboratory supplies and equipment for the entire preparation process.

• Macromolecular Research
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• 제15권6호
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• pp.513-519
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• 2007

Self-assembled nanoparticles have great potential to act as vehicles for hydrophobic drug delivery. Understanding nanoparticle cellular internalization is essential for designing drugs intended for intracellular delivery. Here, the endocytosis and exocytosis of fluorescein isothiocyanate (FITC)-conjugated glycol chitosan (FGC) self-assembled nanoparticles were investigated by flow cytometry and confocal microscopy. The cellular internalization of FGC nanoparticles was initiated by nonspecific interactions between nanoparticles and cell membranes. Although adsorptive endocytosis of the nanoparticles occurred quickly, significant amounts of FGC nanoparticles were exocytosed, particularly in the early stage of endocytosis. The amount of exocytosed nanoparticles was dependent on the pre-incubation time with nanoparticles, suggesting that exocytosis is dependent on the progress of endocytosis. FGC nanoparticles internalized by adsorptive endocytosis were distributed in the cytoplasm, but not in the nucleus. In vitro cell cycle analysis demonstrated that FGC nanoparticles delivered paclitaxel into the cytoplasm and were effective in arresting cancer cell growth.

• Elastomers and Composites
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• 제40권4호
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• pp.272-276
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• 2005

3-aminopropyltrimethoxysilane을 처리한 반응성 있는 유리표면 위에 'dirt-ball' 방법을 사용하여 $C_{70}$-금 나노입자 다중성막 필름을 자기조립하였다. 표면처리한 유리막을 $C_{70}$ 과 ${\omega}$-아미노기를 가진 금 나노입자를 포함하고 있는 용액속에 담그었다. 유기반응(아민화 반응)은 여러층으로 쌓인 다중성막 $C_{70}$-금 나노입자 필름을 용이하게 자기조립 할 수 있었다. $C_{70}$-금 나노입자 필름의 화학적 안정성은 산성용액에 필름을 담근후 흡수도의 변화를 측정함으로 조사되었다. 또한 나노입자 필름의 초음파적 안정성은 초음파 조건에 $C_{70}$-금 나노입자 필름을 노출하여 초음파를 조사 시킨후 고체 표면 위에 부분적인 탈착도의 변화와 작은 정도의 응집성이 일어남을 알 수 있었다.

• 한국세라믹학회지
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• 제42권2호
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• pp.127-131
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• 2005

열처리가 단분산 구형 $SiO_2$ 나노 분말의 자기조립을 통하여 형성된 광자결정 박막의 광특성에 미치는 영향에 대하여 조사하였다. 광밴드갭에 의해 나타나는 반사율 피크는 열처리 온도가 증가함에 따라 단파장 쪽으로 이동하였고, 빛의 회절에 의해 나타나는 Fabry-Perot fringes 피크의 강도도 증가하였다. 또한, 반사율의 절대값도 $250\~300^{\circ}C$ 사이에서 열처리한 시편에서 가장 높은 값을 나타내었다. 미세구조 분석에 따르면 저온열처리를 통하여 입자크기와 결함량이 줄어들고 결정의 치밀도는 증가하였다.