• Biotechnology and Bioprocess Engineering:BBE
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• 제6권4호
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• pp.279-283
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• 2001

Cationic lipid emulsion system consisting of 1, 2-dioleoyl-sn-slycero-3-trimethyl-ammonium-propane(DOTAP) and plasmin DNA with various counterions in the lipid headgroups were prepared. The transfection activity of the cationic lipid emulsion systems was then investigated in vitro and in vivo. The complex formation of plasmid DNA lipid emulsion was affected by the counterions through charged headgroup repulsion and also by the salt concen-tration in the media. As such , the transfection activity of the DOTAP emulsion system can be controlled by changing the counterions.

• Bulletin of the Korean Chemical Society
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• 제34권3호
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• pp.931-935
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• 2013

Lipid events in liposome-mediated transfection (lipofection) are largely unknown. Here we studied whether phospholipase D (PLD), an important enzyme responsible for phospholipid breakdown, was affected during lipofection of HepG2 cells with a luciferase plasmid. Synthetic cholesterol (Chol) derivatives, including $3{\beta}$[L-ornithinamide-carbamoyl]Chol, [polyamidoamine-carbamoyl]Chol and $3{\beta}$[N-(N',N'-dimethylaminoethane)-carbamoyl]Chol, and a cationic lipid, N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride were mixed with a helper lipid dioleoylphosphatidylethanolamine to form respective cationic liposomes. All cationic liposomes were found to stimulate PLD. Although orders of magnitude effects of the cationic liposomes on PLD stimulation did not consistently match those on cytotoxicity and luciferase expression, a causal relationship between PLD activation and cytotoxic effect was remarkable. PLD stimulation by the cationic liposomes was likely due to their amphiphilic characters, leading to membrane perturbation, as supported by similar results obtained with other membrane-perturbing chemicals such as oleate, melittin, and digitonin. Our results suggest that lipofection induces cellular lipid changes such as a PLD-driven phospholipid turnover.

• Journal of Pharmaceutical Investigation
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• 제39권5호
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• pp.339-343
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• 2009

Recently, co-delivery of drug and gene has been attempted for higher therapeutic effects of anticancer agents. In this study, cationic liposomes were prepared using 1,2-dioleoyl-3-trimethylammoniopropane (DOTAP) as a cationic lipid to investigate the effect of drug loading on the physicochemical characteristics of cationic liposomes/DNA complexes. The complex formation between cationic liposomes and negatively charged plasmid DNA was confirmed and the protection from DNase was observed. Particle size of complexes was reduced not by drug loading, but by the increased ratio of cationic lipid to plasmid DNA. Meanwhile, zeta potential of complex was increased by the addition of cationic liposomes to complexes and the effect of drug loading on the zeta potential was not much higher than on particle size. Gel retardation of complexes was indicated when the complexation weight ratios of cationic lipid to plasmid DNA were higher than 24:1 for drug free complexes and 20:1 for drug loaded ones, respectively. Agarose gel retardation showed the similar complexation between plasmid DNA and drug free liposomes or drug loaded liposomes. Both complexes protected plasmid DNA from DNase independent of complexation temperature. From the results, drug loading may affect not the complex formation of cationic liposomes and plasmid DNA, but the particle size of complex.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2187-2192
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• 2012

This study presents a facile way synthesizing disc-like lipid bilyaer nanostructures with a cationic amphiphilic polyelectrolyte. The cationic amphiphilic polyelectrolyte was in a form of partially quarternized copolymer and was synthesized with 2-(dimethylamino)ethyl methacrylate and stearyl methacrylate. At some concentration ranges of the polymer, the addition of the polymer to lipid components during the preparation of bilayer nanostructures resulted in discs with a fairly high yield (~99%). The mechanism for the formation of the nanostructures was discussed based on the physical properties of these nanostructures and by comparing the nanostructures obtained with an anionic amphiphilic polyelectrolyte.

• BMB Reports
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• 제33권6호
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• pp.476-482
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• 2000

In this paper, we report a new cationic lipid composed of L-lysinamide and cholesterol as a potent gene delivery vector. $3{\beta}$[L-Lysinamide-carbamoyl] cholesterol could self-assemble with plasmid DNA forming discrete lipoplexes. From atomic force microscopic images of the complexes, the size distribution was observed to range from 100 to 150 nm in diameter. The transfection efficiency of this amphiphile on different cell lines was evaluated as a micellar solution in the absence of the fusogenic helper lipid, dioleoyl phosphatidyletbanolamine (DOPE). Transfection experiments were performed as a function of charge ratio (lipid/DNA) and transfection time. Cytotoxicity and in vitro transfection efficiency of the amphiphile was demonstrated and compared with those of commercially available Lipofectin and polyethylenimine (PEI).

• 한국미생물·생명공학회지
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• 제34권4호
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• pp.329-334
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• 2006

콜레스테롤 유래의 양이온성 리피드 2-aminoethylcarbamate-cholesterol(Chol-E)를 합성하여 이의 리포좀을 제조하였다. 리포좀은 다양한 비율로 중성지방인 DOPE와 섞어서 만든 후 $100{\sim}200nm$의 membrane으로 extrusion시켜 균일한 리포좀을 제작하여 크기 및 전위를 측정하였다. 형광단백질 및 luciferase plasmid의 발현을 여러가지 세포에서 확인한 결과 우수한 발현양상을 보였으며 혈청이 있는 조건에서도 발현이 증가임을 볼수 있었으며, 합성 ODNs의 전달도 adipocyte cell 에서도 잘 이루어지는 것을 확인할 수 있었다 임상실험에 쓰이는 저독성의 DC-chol에 비교하여도 독성이 적은 리포좀임을 알 수 있으며 혈청하에서도 안정하게 유전자를 전달할 수 있는 응용성이 기대되는 새로운 리포좀을 제조하였음을 알 수 있다.

• Journal of Pharmaceutical Investigation
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• 제38권3호
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• pp.163-169
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• 2008

Liposomes are spherical vesicles composed of lipid bilayer membranes. However, the conventional liposomes have been found to be plagued by rapid opsonization and taken up by the reticuloendothelial system (RES), resulting in shortened circulation time and limited intracellular uptake to target cell. In this study, polyethyleneglycol-cationic liposomes (PCL) containing cationic lipid and DSPE-mPEG were prepared by thin film cast-hydration method. The PEG liposomes had approximately $97.0{\pm}1.3\;nm$ of mean particle diameter and $-21.7{\pm}1.2\;mV$ of zeta potential value. PCL had $96.4{\pm}1.8\;nm$ of mean particle diameter and $-8.7{\pm}1.1\;mV$ of zeta potential value with a decrease of about 10 mV compared to the PEG liposomes. Loading of model drug, doxorubicin (DOX), in liposomes were carried out by using remote loading method and the loading efficiency of DOX in liposomes was about $95.0{\pm}1.9%$. Intracellular uptake and cytotoxicity of PCL were higher than that of PEG liposomes to murine B16F10 melanoma cells. In addition, anti-tumor activity of PCL was similar to that of PEG liposomes on growth of A549 human lung carcinoma in BALB/c mice. Consequently, PCL modified with cationic lipid may be applicable as anticancer drug carriers that can increase intracellular uptake and therapeutic efficacy.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.425.3-426
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• 2002

Cationic lipids have been used as one of the major components for making most promising non-viral gene delivery systems. whereas sodium cholate. an edge activator has been used as a surfactant in making ultradeformable and ultraflexible liposomes called Transfersomes. Using both a cationic lipid, DOTAP and sodium cholate. a newly formulated ultradeformable cationic liposome has been prepared. The average particle size of this formulation was approximately 80nm. (omitted)

• Journal of Microbiology and Biotechnology
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• 제22권6호
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• pp.866-871
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• 2012

A novel cholesterol-based cationic lipid containing a tri-2-hydroxyethylamine head group and ether linker (Chol-THEA) was synthesized and examined as a potent gene delivery vehicle. In the preparation of cationic liposome, the addition of DOPE as helper lipid significantly increased the transfection efficiency. To find the optimum transfection efficiency, we screened various weight ratios of DOPE and liposome/DNA (N/P). The best transfection efficiency was found at the Chol-THEA:DOPE weight ratio of 1:1 and N/P weight ratio of 10~15. Most of the plasmid DNA was retarded by this liposome at the optimum N/P weight ratio of 10. The transfection efficiency of Chol-THEA liposome was compared with DOTAP, Lipofectamine, and DMRIE-C using the luciferase assay and GFP expression. Chol-THEA liposome with low toxicity had better or similar potency of gene delivery compared with commercial liposomes in COS-7, Huh-7, and MCF-7 cells. Therefore, Chol-THEA could be a useful non-viral vector for gene delivery.

• KSBB Journal
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• 제14권3호
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• pp.377-379
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• 1999

CHO/dhfr- 세포에 대해 LipofectAmine$^{TM}$을 이용한 유전자 이입 효율을 증가시키기 위하여 지질과 DNA의 최적 농도를 구하였다. Reporter 유전자로서 GFP 유전자를 이용하였으며, 여러 농도의 지질 DNA로 유전자 이입된 각 세포군에서 나타나는 green fluorescence intensity를 FACS 분석함으로써 유전자 이입 효율을 정량화 할 수 있었다. 그 결과 24-well plate에서 $2.0{\mu}L$LipofectAmine$^{TM}$과 $0.4{\mu}g$ DNA를 조합하여 사용했을 때 최적의 유전자 이입 효율이 나타남을 알 수 있었다. 또한, GFP는 유전자 이입 최적화를 수행하는 데에 여러가지 면에서 유용한 수단이 될 수 있음을 확인할 수 있었다.