• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.262.1-262.1
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• 2014

Lipid peroxidation induces functional deterioration of cell membrane and induces cell death in extreme cases. These phenomena are known to be related generally to the change of physical properties of lipid membrane such as decreased lipid order or increased water penetration. Even though the electric property of lipid membrane is important, there has been no report about the change of electric properties after lipid peroxidation. Herein, we demonstrate the molecular energy band change in red blood cell membrane through peroxidation by air-based atmospheric pressure DBD plasma treatment. Ion-induced secondary electron emission coefficient (${\gamma}$ value) was measured by using home-made gamma-focused ion beam (${\gamma}$-FIB) system and electron energy band was calculated based on the quantum mechanical Auger neutralization theory. The oxidized lipids showed higher gamma values and lower electron work functions, which implies the change of surface charging or electrical conductance. This result suggests that modified electrical properties should play a role in cell signaling under oxidative stress.

• 한국재료학회지
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• 제20권4호
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• pp.187-193
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• 2010

Chromium nitride (CrN) samples with two different layer structures (multilayer and single layer) were coated on bipolar plates of polymer electrolyte membrane fuel cells (PEMFC) using the reactive sputtering method. The effects with respect to layer structure on corrosion resistance and overall cell performance were investigated. A continuous and thin chromium nitride layer ($Cr_{0.48}\;N_{0.52}$) was formed on the surface of the SUS 316L when the nitrogen flow rate was 10 sccm. The electrochemical stability of the coated layers was examined using the potentiodynamic and potentiostatic methods in the simulated corrosive circumstances of the PEMFC under $80^{\circ}C$. Interfacial contact resistance (ICR) between the CrN coated sample and the gas diffusion layer was measured by using Wang's method. A single cell performance test was also conducted. The test results showed that CrN coated SUS316L with multilayer structure had excellent corrosion resistance compared to single layer structures and single cell performance results with $25\;cm^2$ in effective area also showed the same tendency. The difference of the electrochemical properties between the single and multilayer samples was attributed to the Cr interlayer layer, which improved the corrosion resistance. Because the coating layer was damaged by pinholes, the Cr layer prevented the penetration of corrosive media into the substrate. Therefore, the CrN with a multilayer structure is an effective coating method to increase the corrosion resistance and to decrease the ICR for metallic bipolar plates in PEMFC.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2001년도 추계학술발표회 논문집
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• pp.3-11
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• 2001

Fundamental studies at the CSIRO division of Wool technology and ICI on the diffusion of dyes into wool〔1,2〕have let to development of a new approach to wool dyeing. In this method, the cell membrane complex of wool is modified before dyeing by treatment under mildly alkaline conditions with a special chemicals. Wool pretreated with ethoxylated quaternary ammonium salt has an increased rate of dyebath exhaustion and dye penetration early in the dyeing cycle. This enables the treated material to be dyed below the boil for a similar time to the conventional cycle. This technique can be used on untreated and shrinkresist-treated wool and wool/nylon blends. In addition to good macro-levelness and excellent coverage of tippiness, the low temperature dyeing process give higher exhaustion levels of dyestuffs and insect-resist agent and hence cleaner effluent liquors, compared with conventional dyeing process. Low Temperature Dyeing process cause significantly less fiber damage than conventional way. The reduction in damage is reflected in improved processing performance of the dyed wool.

• 한국자기공명학회논문지
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• 제15권1호
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• pp.1-13
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• 2011

9Pbw2 is a 9-mer analog of protaetiamycine derived from the larvae of the beetle Protaetia brevitarsis. Previously, we designed four 9-mer peptide analogues to optimize the balance between the hydrophobicity and cationicity of the peptides and to increase bacterial cell selectivity. Among them, 9Pbw2 has high antibacterial activity without cytotoxicity. The results obtained in previous study suggest that the bactericidal action of 9Pbw2 may be attributed to the inhibition of the functions of intracellular components after penetration of the bacterial cell membrane. In order to understand structure-activity relationships, we determined the three-dimensional structure of 9Pbw2 in 200 mM DPC micelle by NMR spectroscopy. 9Pbw2 has one hydrophobic turn helix from $Trp^3$ to $Arg^8$ and positively charged residues at the N- and C-terminus. This result suggested that positively charged residues from position at the C-terminus in 9Pbw2 may be important for the primary binding to the negatively charged phospholipid head groups in bacterial cell membranes and hydrophobic residues in the middle portion face toward the acyl chains of the hydrophobic lipid in the bacterial cell membrane.

• 대한화장품학회지
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• 제45권2호
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• pp.175-184
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• 2019

상피세포성장인자(epidermal growth factor, EGF)는 인간의 표피 및 진피에서 세포막 수용체와 상호작용을 통하여 세포의 생장 및 증식을 유도하는 기능을 갖고 있다. 이 같은 EGF의 기능은 의료 및 화장품 분야에서 상처치유 의약품 및 노화방지 화장품의 주요원료로 사용되고 있다. 화장품 원료로서 EGF는 피부장벽으로 알려져 있는 피부 각질층의 투과가 잘 안되기 때문에 가지고 있는 본연의 효능을 구현하는 데 문제가 있다. 본 연구에서는 EGF의 경피투과 효율을 개선하기 위하여 피부 투과능이 확인된 거대분자 전송 도메인(macromolecule transduction domain, MTD) 151이 융합된 형태로 재조합 인간 상피세포성장인자 ($MTD_{151}-EGF$)를 개발하였다. $MTD_{151}-EGF$의 유전자가 coding된 vector로 형질전환된 대장균에서 $MTD_{151}-EGF$ 발현시킨 후 정제를 진행하였다. 정제된 MTD-EGF를 대상으로 세포증식시험, 세포독성시험, 생체외 피부흡수시험 그리고 인공피부를 이용한 경피투과능을 평가하였다. 99% 이상 고순도로 정제된 $MTD_{151}-EGF$의 세포증식 활성은 EGF 대비 동등 이상의 수준이었으며, 세포독성은 관찰되지 않았다. 또한, 인공피부 투과모델에서 FITC로 표지된 EGF와 $MTD_{151}-EGF$의 진피층까지의 투과를 공초점 현미경으로 관찰한 결과, $MTD_{151}-EGF$는 EGF 대비 우수한 투과능을 보였으며, 경피흡수 시스템을 이용한 투과물질의 정량분석 결과, EGF 대비 약 16 배 이상 투과량이 많은 것으로 확인되었다. 이러한 결과들은 다양한 활성물질들의 화장품용 원료로서의 경피투과에 MTD가 기존의 물리적인 경피투과 방법을 효율적으로 개선한 대안이 될 것으로 판단된다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.77.1-77.1
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• 2010

Durability problems of gas diffusion layer(GDL) is one of the important issues for accomplishing commercialization of proton exchange membrane fuel cell(PEMFC). GDL is strongly related to the performance of PEMFC because one of the main function of GDL is to work as a path of fuel, air and water. When the GDL is degraded, it causes water balance problems such as the flooding phenomenon. Thus, investigating the durability characteristics of the GDL is important and understanding the GDL degradation process is needed. In this study, the GDLs are degraded by carbon corrosion stress method which is the electrochemical degradation mode. To determine the effects of carbon corrosion of the GDL, 1.45 V of potential is imposed for 96 hours. In this manner, in the previous research, the structure between the substrate and the MPL is weaken. Further investigations are needed to clarify this phenomenon. Therefore, in this study, the carbon corrosion stress method is carried out with GDLs which have various MPL penetration levels and the effects of the MPL penetration level on the characteristics change of the GDL are analyzed. The changes in characteristics are measured with various properties of GDL such as weight, thickness and static contact angle. The degraded GDL shows loss of their properties.

• BMB Reports
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• 제45권2호
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• pp.85-90
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• 2012

Our previous study demonstrated that CopA3, a disulfide dimer of the coprisin peptide analogue (LLCIALRKK), has antibacterial activity. In this study, we assessed whether CopA3 caused cellular toxicity in various mammalian cell lines. CopA3 selectively caused a marked decrease in cell viability in Jurkat T, U937, and AML-2 cells (human leukemia cells), but was not cytotoxic to Caki or Hela cells. Fragmentation of DNA, a marker of apoptosis, was also confirmed in the leukemia cell lines, but not in the other cells. CopA3-induced apoptosis in leukemia cells was mediated by apoptosis inducing factor (AIF), indicating induction of a caspase-independent signaling pathway.

• 대한의생명과학회지
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• 제19권1호
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• pp.32-40
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• 2013

Pluripotent stem cells (PSCs) have enormous potential in the biomedical sciences because they can grow continuously and differentiate into any kind of cell in the body. However, for future application in regenerative medicine, it is still a challenge to control the differentiation of PSCs without using genetic materials. To control the differentiation of PSCs, small molecules might be the best substitute for genetic materials considering the following advantages: small size, which enables penetration of plasma membrane; easy-to-modify structure; and low chance of genetic recombination in treated cells. Herein, we introduce small molecules that induce the neuroectodermal differentiation of mouse embryonic stem cells (ESCs). The small molecules were identified via ESC-based consecutive screenings of small-molecule libraries composed of 324 natural compounds or 93 selected drugs. The natural compounds discovered in the first screening were used to select 93 structurally similar drugs out of 1,200 approved drugs. In the second screening, among the 93 compounds, we found 4 drugs that induced the neuroectodermal differentiation of ESCs. These drugs were progesteroneor corticoid-derivatives. Our results suggest that small molecules targeting the progesterone receptor or glucocorticoid receptor could be used as chemical tools to induce the differentiation of PSCs into a specific germ lineage.

• 공업화학
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• 제29권1호
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• pp.49-55
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• 2018

본 연구에서는 그라비올라의 주성분인 nicotiflorin을 분리하고 그 아글리콘 성분인 kaempferol을 얻어 세포 보호 효과 및 그 보호 메커니즘을 규명하였다. L-Ascorbic acid 및 (+)-${\alpha}$-tocopherol을 대조군으로 하여, $^1O_2$로 유도된 세포 손상에 대해 nicotiflorin 및 kaempferol의 보호 효과를 측정한 결과 nicotiflorin < (+)-${\alpha}$-tocopherol < kaempferol 순으로 보호 효과가 증가하였다. L-Ascorbic acid는 세포 보호 효과를 보이지 않았다. 이들의 세포 보호 효과 메커니즘을 밝히기 위해 singlet oxygen 소광 속도 상수, 자유라디칼 소거 활성, ROS 소거 활성 및 적혈구 세포 침투율을 측정하였다. 실험 결과, kaempferol과 그 배당체인 nicotiflorin의 세포 보호 효과에 있어서 큰 차이는 세포막에의 침투가 가장 큰 요인으로 확인되었다. 대조군 L-ascorbic acid가 항산화능은 크지만 실험 조건에서 세포막에 침투가 잘 안되어 세포 보호 효과가 나타나지 않은 것으로 확인되었다. Kaempferol과 (+)-${\alpha}$-tocopherol의 비교를 통해 세포 침투뿐만 아니라 라디칼 소거활성 및 ROS 소거 활성도 세포 보호 효과에 기여하는 것으로 나타났다. 결론적으로, 광증감 반응으로 유도된 세포막 파괴에 대한 보호작용은 항산화제들의 세포 침투, 자유라디칼 및 ROS 소거 활성이 큰 영향을 미치는 것으로 확인되었다.

• 대한화장품학회지
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• 제31권1호
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• pp.43-49
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• 2005

최근, 민감성 피부가 증가함에 따라 화장품의 안전성이 매우 중요시되고 있으며, 특히 방부제는 화장품 사용에 따른 부작용을 일으킬 수 있는 주요 자극원의 하나로 알려져 있다. 하지만, 방부제의 세포 독성 피부 투과, 유/수 분배, 항균력 비교 및 이를 통한 피부 자극과의 상관성 분석에 관한 연구는 전무한 실정이다. 본 연구의 목적은 상기의 여러 factor를 고려하여 화장품에서 빈번히 사용되고 있는 방부제의 하나인 phenoxyethanol을 이용한 저자극 방부시스템 개발에 관한 것이다. MTT assay를 통하여 human norm기 fibroblast cell에 대한 독성을 평가해 본 결과, 세포 독성은 propylparaben>butylparaben>ethylparaben>methylparaben>triciosan>phenoxyethanol 순으로 확인되어 phenoxyethanol이 다른 방부제에 비해 낮은 세포 독성을 나타낸 반면, 피부 일차자극을 알아보기 위하여 수행한 인체 첩포시험에서는 triclosan, methylparaben에 비해 높은 피부 자극을 나타내었다. 5 ${\~}$ 8 주령의 웅성 무모생쥐의 피부를 적출하여 in vitro Franz diffusion cell system을 이용한 방부제의 피부 투과도를 측정하여 본 결과, 피부 투과도는 phenoxyethanol > methylparaben > ethylparaben > propylparaben > butylparaben > triclosan 순으로 확인되어 세포 독성이 낮은 phenoxyethanol의 높은 피부 자극이 높은 피부 투과도와 연관성이 큰 것을 확인하였다. 따라서, 본 연구에서는 비교적 독성이 낮은 phenoxyethanol의 피부 투과도를 감소시킬 수 있는 방법을 찾고자 하였으며, 연구 결과, 제형내 polarity가 낮은 oil을 사용할 경우 phenoxyethanol의 피부 투과가 현격히 감소하며, 피부 자극도 감소함을 알 수 있었다. Oil polarity에 따른 Phenoxyethanol의 유/수 분배 측정 결과, Polarity가 낮은 oil에서는 $70\%$ 이상의 Phenoxyethanol이 수상에 존재한 반면, polarity가 높은 oil에서는 약 $70 {\~} 90\%$의 phenoxyethanol이 유상에 존재하였다. 또한, 미생물에 대한 항균력도 phenoxyethanol이 수상에 많이 존재할수록 증가하는 경향을 나타내었다. 따라서, 제형 내 oil tomposition을 변화시킴으로써 phenoxyethanol의 사용량을 줄일 수 있을 뿐만 아니라, 피부 투과를 감소시켜 보다 피부 자극이 적은 저자극 방부시스템 개발이 가능하리라 보여 진다.