• 한국자기공명학회논문지
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• 제15권1호
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• pp.25-39
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• 2011

Syndecan-4 is a transmembrane heparan sulfate proteoglycan, which is a coreceptor with integrins in cell adhesion. To get better understand the mechanism and function of Syndecan-4, it is critical to elucidate the three-dimensional structure of a single transmembrane spanning region of them. Unfortunately, it is hard to prepare the peptide because syndecan-4 is membrane-bound protein that transverse the lipid bilayer of the cell membrane. Generally, the preparation of transmembrane peptide sample is seriously difficult and time-consuming. In fact, high yield production of transmembrane peptides has been limited by experimental adversities of insufficient yields and low solubility of peptide. Here, we demonstrate experimental processes and results to optimize expression, purification, and NMR measurement condition of Syndecan-4 transmembrane peptide.

• KSBB Journal
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• 제32권2호
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• pp.160-167
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• 2017

Coating of individual cells with organic or inorganic materials has drawn a great deal of attention, because it provides the cells with physicochemical durability, which would contribute to the development of bioreactors, biosensor, and lab-on-a-chip, as well as to the fundamental studies in single cell-based biology. Although many strategies have been developed for coating of microbial cells, limited methods are available to coat mammalian cells because most mammalian cells do not have a robust membrane or exoskeleton. Instead, they are enclosed in a lipid bilayer, which is fluidic and vulnerable to changes in its environments. It is more difficult to treat mammalian cells in vitro than microbial cells because the surfaces of mammalian cells are not protected or reinforced by a tough coat. In this work, we report a cytocompatible and degradable nanocoat for mammalian cells. Three types of mammalian cells (HeLa cells, NIH 3T3 fibroblasts, and Jurkat T cells) were individually coated within metal-polyphenol. To maintain the viability of the mammalian cells, we performed the whole processes under strictly physiological culture conditions, and carefully selected nontoxic materials.

• 한국응용과학기술학회지
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• 제25권3호
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• pp.313-321
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• 2008

오래전부터, 많은 여성들은 자신들의 젊음을 연장하고, 외모를 더 아름답게 가꾸고, 이를 죽을 때까지 유지하는 것을 바래왔다. 이에 의사와 약사들뿐만 아니라, 많은 화장품 연구자들도 노화와 관련된 기술개발에 총력을 기울여 왔다. 따라서, 이들 연구자들은 노화방지를 위한 새로운 원료를 찾고, 이를 안정화하고, 피부로 전달하는 기술개발에 항상 관심을 쏟아왔다. 뛰어난 노화방지 화장품 개발을 위해서, Ubiquinone의 일종인 ldebenone에 대해 연구하였고, 이를 비수계 피부유사막 기술을 가지고 캡슐화하고 약물전달하는 연구를 진행하였다. 먼저, 편광현미경(PM, Polarized Microscope), X-선 회절분석(XRD, X-ray Diffractions) 및 시차주사열량계 (DSC, Differential Scanning Calorimetry)를 이용하여 Idebenone을 담지한 피부유사막 액정을 비수계 조건에서 구조 및 열적특성을 조사하였다. 그 결과 비수계 조건에서도 규칙적으로 패킹(Packing)된 지질이중층(Lipid bilayer)과 용매의 연속층으로 이루어진 고밀집된 라멜라(Lamella) 구조의 형성유무와 이때의 상거동을 확인할 수 있었다. 결론적으로 높은 극성도로인해 물분자와 접촉하면 불안정해지는 경향이 있는 Idebenone을 비수계 조건에서 각질층(SC, Stratum Corneum)과 구조 및 조성이 유사한 피부유사막을 디자인하여 안정하게 캡슐화 하였다. 이를 적용한 화장품은 모든 보관조건에서 유화입자의 안정성을 유지함을 확인하였고, Idebenone의 활성역가 또한 $40^{\circ}C$에서 6개월 동안 약 90%이상을 유지하는 우수한 결과를 나타냈다.

• Bulletin of the Korean Chemical Society
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• 제34권4호
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• pp.1120-1126
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• 2013

The syndecan family consists of four transmembrane heparan sulfate proteoglycans present in most cell types and each syndecan shares a common structure containing a heparan sulfate modified extracellular domain, a single transmembrane domain and a C-terminal cytoplasmic domain. To get a better understanding of the mechanism and function of syndecan-4 which is one of the syndecan family, it is crucial to investigate its three-dimensional structure. Unfortunately, it is difficult to prepare the peptide because it is membrane-bound protein that transverses the lipid bilayer of the cell membrane. Here, we optimize the expression, purification, and characterization of transmembrane, cytoplasmic and short extracellular domains of syndecan4 (syndecan-4 eTC). Syndecan-4 eTC was successfully obtained with high purity and yield from the M9 medium. The structural information of syndecan-4 eTC was investigated by MALDI-TOF mass (MS) spectrometry, circular dichroism (CD) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. It was confirmed that syndecan-4 eTC had an ${\alpha}$-helical multimeric structure like transmembrane domain of syndecan-4 (syndecan-4 TM) in membrane environments.

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.3998-4002
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• 2012

With continuing progress of nanotechnologies and various applications of nanoparticles, one needs to develop a quick and fairly standard assessment tool to evaluate cytotoxicity of nanoparticles. However, much cytotoxicity studies on the interpretation of the interaction between nanoparticles and cells are non-mechanistic and time-consuming. Here, we propose a simple screening method for the analysis of the interaction between several AgNPs (5.3 to 64 nm) and fluorescence-dye containing vesicles ($12{\mu}m$) acting as a biomimetic cell-membrane. Fluorescence-dye containing vesicle was prepared using a fluorescence probe (1,6-diphenyl-1,3,5-hexatryene), which was intercalated into the lipid bilayer due to their hydrophobicity. Zeta potential of all materials except for bare-AgNPs (+32.8 mV) was negative (-26 to -54 mV). The morphological change (i.e., rupture and fusion of vesicle, and release of dye) after mixing of the vesicle and AgNPs was observed by fluorescence microscopy, and fluorescence image were different with coating materials and surface charge of x-AgNPs. In the results, we found that the surface charge of nanoparticles is the key factor for vesicle rupture and fusion. This proposed method might be useful for analyzing the cytotoxicity of nanoparticles with cell-membranes instead of in vitro or in vivo cytotoxicity tests.

• Bulletin of the Korean Chemical Society
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• 제7권1호
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• pp.78-81
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• 1986

The photosensitized lysis of egg lecithin lipid membranes (liposomes) have been performed to UV-B light (270-320 nm) by L-tryptophan(L-Trp) and its peptide such as N-acetylphenylalanyl-L-tryptophan(NAPT) incorporated in the liposomes(ca. 0.1% by weight) or in the external buffer (0.1-0.3 mM). Requirement of oxygenation suggests that the lysis of liposomes is caused by the photosensitized oxidation of lipids. There was significant protection against lysis photosensitized by Trp in the external buffer by low concentration of ferricyanide (0.8 mM), but there was no effect on the lytic efficiency by $N_3^-$ which is singlet oxygen($^1O_2$) quencher, indicative of an electron transfer mechanism involved in the photosensitization. The small change of the lytic efficiency with increasing pH from 4 to 9 was interpreted by large target theory and subsequently indicates that superoxide($O_2^-$) may be an active intermediate for the oxidation. The efficiency of photosensitization of Trp was higher than that of NAPT under the same experimental condition. The weak lytic efficiency of liposomes photosensitized by NAPT was enhanced by incorporating NAPT in liposomes, but it was again quenched by ${\beta}$-carotene incorporated in the bilayer of liposomes. These results indicate that a portion of liposome lysis may be due to $^1O_2$ formation from the excited NAPT.

• Molecules and Cells
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• 제45권9호
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• pp.603-609
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• 2022

Cells can communicate in a variety of ways, such as by contacting each other or by secreting certain factors. Recently, extracellular vesicles (EVs) have been proposed to be mediators of cell communication. EVs are small vesicles with a lipid bilayer membrane that are secreted by cells and contain DNA, RNAs, lipids, and proteins. These EVs are secreted from various cell types and can migrate and be internalized by recipient cells that are the same or different than those that secrete them. EVs harboring various components are involved in regulating gene expression in recipient cells. These EVs may also play important roles in the senescence of cells and the accumulation of senescent cells in the body. Studies on the function of EVs in senescent cells and the mechanisms through which nonsenescent and senescent cells communicate through EVs are being actively conducted. Here, we summarize studies suggesting that EVs secreted from senescent cells can promote the senescence of other cells and that EVs secreted from nonsenescent cells can rejuvenate senescent cells. In addition, we discuss the functional components (proteins, RNAs, and other molecules) enclosed in EVs that enter recipient cells.

• 한국축산식품학회지
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• 제42권2호
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• pp.197-209
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• 2022

Extracellular vesicles (EVs) are nanosized vesicles secreted from cells into the extracellular environment and are composed of a lipid bilayer that contains cargos with biological activity, such as lipids, proteins, mRNAs, and noncoding microRNAs (miRNAs). Due to their biological activity and their role in cell-to-cell communication, interest in EVs is rapidly increasing. Bovine milk is a food consumed by people of all ages around the world that contains not only a significant amount of nutrients but also EVs. Milk-derived EVs also exhibit biological activity similar to other source-derived EVs, and studies on bovine milk EVs have been conducted in various research fields regarding sufficient milk production. In particular, not only are the effects of milk EVs themselves being studied, but the possibility of using them as drug carriers or biomarkers is also being studied. In this review, the characteristics and cargo of milk EVs are summarized, as well as their uptake and stability, efficacy and biological effects as carriers, and future research directions are presented.

• 한국식품과학회지
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• 제28권1호
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• pp.1-7
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• 1996

Hydrocolloid film에 lipid 액을 입혀 제조한 film A와 hydrocolloid 용액에 beeswax의 함량과 용해 상태를 달리하여 제조한 film B와 C의 물리적 특성을 검토해 본 결과, 제조에 있어서는 film A보다 film B와 C의 제조가 용이하였다. 세가지 film의 두께는 0.03 mm 정도로 유의적인 차이를 나타내지 않았으며, 1-3%의 수분함량과 59-68%의 지방을 함유한 film으로 세 film 모두 백색을 나타내었다. 인장강도는 film A가 우수하였으며, 투습도에서는 lipid 액의 뚜렷한 효과로 감소하였으며 film A와 B는 유의적인 차이를 나타내지 않았다. 한편 냉동전후의 투습도에서 film A는 유의적인 차이를 나타내지 않았으나, film B와 C는 냉동 후의 투습도가 유의적으로 감소하였다. 산소투과도는 film A와 C가 유의적인 차이를 나타내지 않았다. 전자현미경으로 film의 표면특성을 관찰한 결과, film A는 지방구의 분포가 일정하였으나 B와 C는 지방구의 편재를 볼 수 있었으며 1년 저장 후 film A는 bilayer층의 delamination을 나타내는 것으로 보아 전반적인 물리적 특성은 film A가 우수하나 장기저장에 있어서는 보다 제조법이 용이한 film B와 C를 선택하는 것이 바람직할 것으로 보이며, film B와 C의 균일하지 못한 표면 형상을 개선하는 방법과 투습도 및 산소투과도를 감소시키는 것이 앞으로 개선할 과제로 여겨진다.

• 대한화학회지
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• 제50권3호
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• pp.216-223
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• 2006

혈류 내에서 리포솜의 안정성을 향상시키기 위해 지질-고분자 유도체를 지질 이중층에 도입하거나 친수성 고분자를 리포솜에 결합시켜 리포솜의 표면을 개질하는 방법이 개발되어왔다. 본 연구에서는 비닐 단량체로서 히드록시에틸메타크릴레이트(HEMA)와 히드록시폴리옥시에틸렌메타크릴레이트(HPOEM)를 자유 라디칼 중합하여 측쇄에 다수의 폴리에틸렌옥사이드를 갖는 빗(Comb) 모양 공중합체인 poly(HEMA-co-HPOEM)를 제조하였다. Poly(HEMA-co-HPOEM)를 리포솜의 표면에 결합시키고 혈장 용액 내에서 개질된 리포솜의 특성을 살펴보았다. Poly(HEMA-co-HPOEM)으로 개질된 리포솜의 입자크기는 대조군 리포솜에 비해 약 30 nm 증가하였고 리포솜 표면의 음전하를 차폐하여 제타 포텐셜의 절대값은 감소하였다. 리포솜 내부에 모델약물인 독소루비신(Doxorubicin)의 로딩효율은 ~ 90%로서 리포솜 표면에 결합된 poly(HEMA-co-HPOEM)는 약물의 로딩효율에 영향을 주지 않았다. 혈장 내에서 리포솜의 안정성을 평가한 결과, 빗 모양 고분자로 수식한 리포솜의 입자크기는 증가하지 않았고 단백질 흡착은 대조군 리포솜 또는 폴리에틸렌옥사이드-지질 유도체가 도입된 리포솜(PEG-리포솜)에 비해 감소되어 빗 모양 고분자인 poly(HEMA-co-HPOEM)이 혈류 내 리포솜의 안정성 향상에 효과적임을 확인하였다.