• 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.427.1-427.1
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• 2002

To improve stability and transfection efficiency, a novel combination of cationic emulsion and galactosylated chitosan was developed for targeted gene delivery. Six formulations of cationic liposome and our novel emulsion were prepared for comparison of stability and transfection efficiency. Cationic liposomes composed of 3［N-(N.N dimethylaminoethylene) carbamoyl］ cholesterol (DC-Chol) and dioleyl phophatidyl ethanolamine (DOPE) were prepared by extrusion method and cationic emulsions composed of DC-Chol. DOPE. castor oil, and Tween 80 were prepared by sonication method. (omitted)

• 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.236.1-236.1
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• 2002

Mucosal administration of drug or therapeutic gene is emerging as a new route of delivery for systemic and local therapeutics. Previously. in situ gelling system has been applied to chemical drug such as acetaminophen. insulin. prostaglandin E1. and clotrimazole. Plasmid DNA has not been delivered in form of in situ gelling vehicles. To improve the intranasal absorption of plasmid DNA. we designed delivery systems composed of provide of in 냐셔 gelling and mucoadhesive polymers. (omitted)

• Korean Chemical Engineering Research
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• 제58권3호
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• pp.450-457
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• 2020

선행된 연구에서 Yo-Pro-1의 전달 효율의 경향과 CFP 유전자의 발현 효율의 경향이 큰 차이를 보였지만 이 문제에 대한 원인을 제시할 수 없었다. 따라서 본 연구에서는 형광 염료를 이용하여 DNA에 표지 후 전달 효율을 정량화함으로써 이 문제에 대한 원인을 찾고자 한다. 표지를 위한 형광 염료로 Yo-Pro-1을 사용하였으며, Yo-Pro-1과 표지 된 DNA의 전달 효율을 비교하였다. 전압 조건에 따른 전달효율 비교에서는 Yo-Pro-1과 Yo-Pro-1으로 표지 된 DNA의 전달 효율 모두 96 V에서 전달 효율이 최대가 되었으며 전압이 더 증가하면 전달 효율이 오히려 감소하는 경향을 보였다. 전압 인가 횟수 조건에 따른 전달 효율 비교에서는 Yo-Pro-1과 Yo-Pro-1으로 표지 된 DNA의 두 전달 물질 모두 8회의 전압 인가 횟수에서 전달 효율이 최대가 되었으며 전압 인가 횟수가 더 증가하면 전달 효율이 감소하는 경향을 보였다. 두 결과를 통해 디지털 전기천공시스템에서 Yo-Pro-1을 사용한 전달 효율 측정이 DNA의 전달 효율을 잘 대변하는 것을 확인하였다. 또한, 본 연구의 결과를 통해 선행된 연구에서 보인 Yo-Pro-1의 전달 효율의 경향과 CFP 유전자의 발현 효율의 경향 차이는 전달 물질의 전달 효율 차이에서 기인한 결과가 아닌 전달 된 유전 물질의 발현 과정에서의 문제로 인한 결과임을 추론해 볼 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제27권9호
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• pp.1335-1340
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• 2006

It has been found that a number of diseases are associated with mutations in the mitochondrial DNA. Therapeutic gene delivery to mitochondria has been suggested as a clinical option for these diseases. In this study, we developed a gene carrier to mitochondria by the conjugation of mitochondrial leader peptide (LP) to polyethylenimine (PEI). Mitochondrial LP conjugated PEI (PEI-LP) was synthesized with low molecular weight PEI (2,000 Da, PEI2K). Gel retardation assay showed that PEI2K-LP formed complexes at a 1.0/1 weight ratio. In addition, PEI2K-LP protected DNA from the enzymatic degradation for at least 60 min, while naked DNA was completely degraded within 20 min. PEI2K-LP was compared with LP conjugated high molecular weight PEI (25,000 Da, PEI25K) in terms of toxicity and delivery efficiency. MTT assay showed that PEI2K-LP had much lower cytotoxicity than PEI25K-LP to 293 cells. In addition, cell-free DNA delivery assay showed that PEI2K-LP delivered more DNA to mitochondria at a 1.8/1 weight ratio than naked DNA or PEI. This result suggests that PEI2K-LP may be useful for the development of mitochondrial gene therapy system with lower cytotoxicity.

• Journal of Pharmaceutical Investigation
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• 제28권2호
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• pp.93-98
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• 1998

We have developed liposomes which can be easily prepared with inexpensive lipid, have enhanced stability, and can efficiently deliver DNA into the COS-l cells, Liposome formulations were prepared using cationic materials such as dimethyldioctadecyl ammonium bromide (DDAB), cetyltrimethyl ammonium bromide(CTAB), We investigated the effect of cationic liposome formulations on in vitro DNA transfection, DDAB-containing liposomes showed increased transfection efficiency which was 3.2-fold as much as that by $Lipofectin^{\circledR}$, but CTAB-containing liposomes were inactive in gene transfection. The effect of colipid of DDAB-containing liposome was also investegated. As a colipid, dioleylphosphatidylethanolamine(DOPE) and cholesterol did altered the transfection efficiency of DDAB-containing liposomes. And increased DDAB concentration lowered the transfection efficiency. The optimum amount of liposomal formulation was $10\;{\mu}M$ for $1\;{\mu}g$ of DNA. In the experiment of stability, DOPE-containing liposomes formulation showed a broad size distribution and separation of two major peaks on a 5th day of preparation, but liposomes containing cholesterol was stable for 10 days. DDAB-containing liposomal DNA delivery system was prepared easily and was stable.

• Journal of Microbiology and Biotechnology
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• 제21권8호
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• pp.802-807
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• 2011

Cationic liposomes have been actively used as gene delivery vehicle because of their minimal toxicity, but their relatively low efficiency of gene delivery is the major disadvantage of these vectors. Recently, cysteine residue incorporation to HIV-1 Tat peptide increased liposomemediated transfection compared with unmodified Tat peptide. Therefore, we designed a novel modified Tat peptide having a homodimeric (Tat-CTHD, Tat-NTHD) and closed structure (cyclic Tat) simply by using the disulfide bond between cysteines to develop a more efficient and safe nonviral gene delivery system. The mixing of Tat-CTHD and Tat-NTHD with DNA before mixing with lipofectamine increased the transfection efficiency compared with unmodified Tat peptide and lipofectamine only in MCF-7 breast cancer cells and rat vascular smooth muscle cells. However, cyclic Tat did not show any improvement in the transfection efficiency. In the gel retardation assay, Tat-CTHD and Tat-NTHD showed more strong binding with DNA than unmodified Tat and cyclic Tat peptide. This enhancement was only shown when Tat-CTHD and Tat-NTHD were mixed with DNA before mixing with lipofectamine. The effects of Tat- CTHD and Tat-NTHD were also valid in the experiment using DOTAP and DMRIE instead of lipofectamine. We could not find any significant cytotoxicity in the working concentration and more usage of these peptides. In conclusion, we have designed a novel transfection-enhancing peptide by easy homodimerization of Tat peptide, and the simple mix of these novel peptides with DNA increased the gene transfer of cationic lipids more efficiently with no additional cytotoxicity.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.582-586
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• 2003

There has been interest in developing gene therapy based on naked plasmid DNA for treating serum protein deficiencies and human erythropoietin (hEPO) is one of the candidate for gene therapy being Investigated most enthusiastically. We constructed novel plasmid DNA vectors pVAC-hEPOI/II/III which contain one, two, three hEPO gene(s) respectively for producing high level expression and secretion of hEPO in vitro and in vivo. NIH3T3 and COS7 cells were transfected transiently with these vectors and increase in hEPO expression in medium reached 2-5 fold in comparison with pSecTagB-hEPO. Intra muscular administrations of pVAC-hEPOI/II/III vectors into mice resulted in high level secretion of hEPO in the serum and corresponding increases in hematocrit level. In conclusion the transduction efficiency of naked plasmid vectors is one of the critical factors of a gene delivery system and these novel plasmid vectors will contribute to various gene therapy based on naked plasmid DNA.

• 폴리머
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• 제33권3호
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• pp.213-218
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• 2009

1,2-Dioleoyl-3-trimethylammonium-propane(DOTAP)와 Tween80, squalene을 포함하는 양이온성 지질 에멀젼을 기반으로 효율적인 비바이러스성 유전자 전달체를 개발하였다. 유전자 전달체의 발현효율을 증가시키기 위해 암세포에 표적지향성을 가지는 folate를 수식한 PEG-DPPE를 사용하였다. Folate-PEG-DPPE를 포함하는 양이온성 지질 에멀젼으로 HeLa 세포주와 293 세포주에 유전자 형질발현 실험을 하였다. HeLa 세포는 folate에 민감한 세포주이다. 양이온성 지질 에멀젼의 입자필기와 DNA/lipid 복합체의 크기는 각각 205.6 nm와 150.5 nm로 측정되었다. 양이온성 지질 시스템/DNA(4:1(w:w)) 복합체의 유전자 발현효율은 folate의 표적화 영향으로 인해 DOTAP만 있는 에멀젼에 비하여 100배 이상 더 높은 것으로 나타났다.

• Archives of Pharmacal Research
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• 제28권6호
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• pp.722-729
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• 2005

With the aim to improve the specificity and to reduce the cytotoxicity of polyethylenimine (PEI), we have synthesized the conjugates of the branched PEI (25 kDa) with transferrin. The trans-ferrin-PEI (TP) conjugates with five compositions were synthesized using periodate oxidation method and confirmed by FT-IR spectroscopy and gel permeation chromatography. The free amine contents of TP conjugates, which were able to condense and deliver DNA, increased as the amount of PEI increased. TP/DNA polyplexes were characterized by measuring gel elec-trophoresis, ethidium bromide fluorescence quenching, particle size and zeta potential of complexes. Complete complexation of the polyplexes was observed above the N/P ratio of 5 in TP/DNA, and above 3 in PEI/DNA, respectively. The zeta potential of the complexes decreased as the amount of transferrin in TP conjugates increased. Transfection efficiency of TP conjugates was evaluated in HeLa cell and Jurkat cell systems. Among the five compositions of TP conjugates, TP-2 system mediated a higher $\beta$-galactosidase gene expression than PEI system in Jurkat cell which was known to express elevated numbers of transferrin receptors. From the results of the cell viability based on MTT assay, TP conjugates showed lower cytotoxicity com-pared with the PEI system. We expect that the TP conjugate can be used efficiently as a non-viral gene delivery vector.

• Journal of Plant Biotechnology
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• 제7권2호
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• pp.113-121
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• 2005

The objective of this study was to identify the major parameters controlling DNA delivery by particle bombardment to immature embryos of Chinese spring wheat (Triticum aestivum L.). Efficiency of DNA (uidA gene) delivery was assessed by transient GUS (${\beta}$-glucuronidase) expression in bombarded tissues. Of the parameters analyzed, acceleration pressure, bombardment distance, chamber vacuum pressure, bombardment times, osmotic conditioning of culture had a remarkable influence on transient gene expression. A bombardment procedure suitable for Chinese spring wheat cultivars was developed which allowed high-efficiency DNA delivery combined with reduced damage to target tissues. The high efficiency made the system practical for wheat genetic transformation research and accelerating wheat breeding programs.