• Bulletin of the Korean Chemical Society
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• 제35권9호
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• pp.2621-2624
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• 2014

The rapid and spontaneous adsorption of proteins on nanoparticle (NP) surfaces in biological fluids such as blood is an important phenomenon as it possibly determines "what the cells see" and, thus, the fates of NPs in living organisms. In order to quantitatively understand protein coronas at the molecular level, we investigated human serum albumin (HSA) coronas that were produced on silica NPs of 20 nm and 50 nm diameters using conventional gel electrophoresis. Analysis of the concentration dependence of protein adsorption showed that HSA coronas preferentially formed a monolayer on silica NPs and revealed the presence of hard protein coronas. HSA adsorption was clearly dependent on NP size, and this might be due to the different surface curvatures of NPs of different sizes.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.360-360
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• 2011

We demonstrated the fabrication method of superhydrophobic nanocoating through a facile spin-coating and the chemical modification. The resulting coating showed a tremendous water repellency with a static water contact angle (CA) of 158$^{\circ}$ and a hysteresis of 1$^{\circ}$. The number of ZnO nanoparticle (NP) coating cycles affected on the surface roughness, which is key role for superhydrophobic surface, and thus the CA can be modulated by changing the ZnO NP coating cycles. The CA can be controlled by changing the carbon length of Self-Assembled Monolayers(SAM). This simple ZnO coating is substrate-independent including flexible surfaces, papers and cotton fabrics, which can effectively be used in various potential applications. We also observed the thermal and dynamic stabilities of SAM on ZnO nanoparticles. The superhydrophobicic surface maintained its superhydrophobic properties below 250$^{\circ}C$ and under dynamic conditions.

• Macromolecular Research
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• 제15권3호
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• pp.211-215
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• 2007

Hybrid thin film nanostructures composed of metal nanoparticles (NPs) and self-assembled polymer films with different spatial distributions of NPs were analyzed by optical waveguide spectroscopy (OWS). Specifically, the dielectric constants were calculated using effective medium theory for the incorporation of 1 vol% Au NP into the block copolymer (BCP) films having a cylindrical nanodomain morphology. Three cases were considered: uniform distribution of NPs in the film; selective distribution of NPs only in the cylindrical domains; and segregation of NPs to the center of the cylindrical domains. The optical waveguide spectra derived from the calculated dielectric constants demonstrate the feasibility of experimentally distinguishing the composite nanostructures with different inner morphologies in the hybrid metal NP-BCP nanostructures, by the measurement of the dielectric constants using OWS.

• Current Photovoltaic Research
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• 제4권2호
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• pp.64-67
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• 2016

We investigated the influences of Ag nanoparticle (NP) arrays and surface nanohole (NH) patterns on the optical characteristics of 10-${\mu}m$-thick c-Si wafers using finite-difference time-domain (FDTD) simulations. In particular, we comparatively studied the plasmonic effects of both monomer arrays (MA) and heptamer arrays (HA) consisting of identical Ag NPs. HA improved the optical absorption of the c-Si wafers in much wider wavelength range than MA, with the help of hybridized plasmon modes. The light trapping capability of the NH array pattern is superior to that of the Ag plasmonic NPs. We also found that the addition of the Ag HA on the wafers with surface NH patterns further enhanced optical absorption: the expected short-circuit current density was as high as $34.96mA/cm^2$.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3191-3195
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• 2012

New silver nanoparticle (AgNP)-loaded amino acid based hydrogels were synthesized successfully from poly (vinyl alcohol) (PVA) and poly(acryl amide-co-acryloyl phenyl alanine) (PAA) by redox polymerization. The formation of AgNP in hydrogels was confirmed by using a UV-Vis spectrophotometer and XRD. The structure and morphology of silver nanocomposite hydrogels were studied by using a scanning electron microscopy (SEM), which demonstrated scattered nanoparticles, ca. 10-20 nm. Thermogravimetric analysis revealed large differences of weight loss (i.e., 48%) between the prestine hydrogel and silver nanocomposite. The antibacterial studies of AgNP-loaded PAA (Ag-PAA) hydrogels was evaluated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria. These Ag-PAA hydrogels showed significant activities against all the test bacteria. Newly developed hydrogels could be used for medical applications, such as artificial burn dressings.

• 폴리머
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• 제36권1호
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• pp.71-75
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• 2012

본 연구는 폴리(비닐 알코올)(PVA) 하이드로젤 안에 $AgNO_3$ 용액을 이용하여 은 나노입자(AgNPs)를 제조하였다. PVA 입자를 증류수에 용해시킨 후, 50 kGy 감마선을 조사하여 PVA 하이드로젤을 제조하였다. 감마선을 이용하여 제조된 PVA 하이드로젤을 0.01, 0.05 M 질산은 수용액에 1시간 동안 침지후, 팽윤된 하이드로젤을 꺼내 감마선을 재조사하여 PVA 하이드로젤 내부에 AgNPs를 제조하였다. AgNPs가 함유된 PVA 하이드로젤의 UV 흡수 특성 및 FE-SEM 측정 결과, 감마선 조사량이 증가할수록 AgNPs의 생성이 증가하는 것을 확인할 수 있었으며, 같은 조사량에서 $AgNO_3$ 용액의 농도가 클수록 AgNPs 생성이 증가하였다. 액체배지 및 고체배지를 이용하여 그람 음성 세균인 E.coli와 S.aureus에 대한 PVA 하이드로젤에 생성된 AgNPs의 항균 실험 결과 매우 우수한 항균 효과를 나타냈다.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.1973-1978
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• 2014

Here, we present a facile method to synthesize Pt nanoparticles (NPs) and graphene composite materials (Pt/G) via vacuum filtration. Anodic aluminum oxide (AAO) templates were used to separate Pt/G composite and liquid phase. This method can be used to easily tune the mass ratio of Pt NPs and graphene. Pt NPs, graphene, and carbon nanotubes (CNTs) as building blocks were characterized by a variety of techniques such as scanning electron microscopy, UV-Vis spectroscopy, and Raman spectroscopy. We compared the electrocatalytic activities of Pt/G with Pt NP and CNT films (Pt/CNT) by cyclic voltammetry (CV), CO oxidation, and methanol oxidation. Pt/G was much more stable than pure Pt films. Also, Pt/G had better electrochemical activity, CO tolerance and methanol oxidation than Pt/CNT loaded with the same amount of Pt NPs due to the better dispersion of Pt NPs on graphene flakes without aggregation. We further synthesized Au@Pt disk/G and Pt nanorods/G to determine if our synthetic method can be applied to other NP shapes such as nanodisks and nanorods, for further electrocatalysis studies.

• 한국전기전자재료학회논문지
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• 제35권5호
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• pp.439-444
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• 2022

Laser-induced plasmonic sintering of metal nanoparticles (NPs) is a promising technology to fabricate flexible conducting electrodes, since it provides instantaneous, simple, and scalable manufacturing strategies without requiring costly facilities and complex processes. However, the metal NPs are quite expensive because complicated synthesis procedures are needed to achieve long-term reliability with regard to chemical deterioration and NP aggregation. Herein, we report laser-induced Ag NP self-generation and sequential sintering process based on low-cost Ag organometallic material for demonstrating high-quality microelectrodes. Upon the irradiation of laser with 532 nm wavelength, pre-baked Ag organometallic film coated on a transparent polyimide substrate was transformed into a high-performance Ag conductor (resistivity of 2.2 × 10^-4 Ω·cm). To verify the practical usefulness of the technology, we successfully demonstrated a wearable transparent heater by using Ag-mesh transparent electrodes, which exhibited a high transmittance of 80% and low sheet resistance of 7 Ω/square.

• 대한수의학회지
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• 제57권4호
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• pp.215-222
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• 2017

Temporal and subcellular distributions of hyaluronic acid (HA) as a degradable nanoparticle (NP) in animals were investigated to determine if HA-NP could be utilized as an appropriate drug delivery system. After mice were intravenously injected with 5 mg/kg of Cy5.5-labeled HA-NP sized 350-400 nm or larger HA-polymers, the fluorescence intensity was measured in all homogenized organs from 0.5 h to 28 days. HA-NP was greatly detected in spleen, liver and kidney until day 28, while it was maintained at low levels in other organs. HA-polymer was observed at low levels in all organs. HA-NP quantities in spleen and liver were reduced until day 3, but increased sharply between days 3 and 7, then decreased again, while their HA-polymers were maintained at low levels until day 28. In kidneys, both HA-NP and HA-polymer showed high levels after 0.5 h of administration, but steadily decreased until day 28. According to ultrastructural analyses, HA-NP was engulfed in Kupffer cells of liver and macrophages of spleen and kidney at day 1 and was accumulated in the cytoplasm of kidney tubular cells at day 7. Overall, these findings suggest that HA-NP could be considered a desirable drug carrier in the liver, kidney, or spleen.

• Journal of Microbiology and Biotechnology
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• 제27권8호
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• pp.1483-1490
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• 2017

In this study, silver nanoparticles (AgNPs) were synthesized by the citrate reduction process and, with the assistance of n-hydroxysuccinimide and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, were successfully loaded with the macromolecular drug vancomycin (VAM) to form AgNP-VAM bioconjugates. The synthesized AgNPs, VAM, and AgNP-VAM conjugate were characterized by UV-visible spectroscopy, zeta potential analysis, confocal microscopy, and transmission electron microscopy. The effect of loading VAM onto AgNPs was investigated by testing the internalization of the bioconjugate into Mycobacterium smegmatis. After treatment with the AgNP-VAM conjugate, the bacterial cells showed a significant decrease in UV absorption, indicating that loading of the VAM on AgNPs had vastly improved the drug's internalization compared with that of AgNPs. All the experimental assessments showed that, compared with free AgNPs and VAM, enhanced internalization had been successfully achieved with the AgNP-VAM conjugate, thus leading to significantly better delivery of the macromolecular drug into the M. smegmatis cell. The current research provides a new potential drug delivery system for the treatment of mycobacterial infections.