• Proceedings of the PSK Conference
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• 2003.04a
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• pp.315.2-316
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• 2003

Polyethylenimine (PEI) has been used as a non-viral gene delivery carrier. To improve the efficacy of transfection, transferrin was incorporated by covalent linkage to PEI. As a model plasmid DNA, pHME185/b-gal, a mammalian expression vector was used. The transferrin-polyethylenimine (TfPEI) was synthesized by conjugate PEI with transferrin using sodium periodateand and characterized by FT-IR and 1H-NMR. (omitted)

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.4
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• pp.269-273
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• 2001

This study presents a new formulation method for improving DNA transfection effi-ciency using a fusogenic peptide and polyethylene glycol-grafted polyethylenimine. Succinimidyls succinate polyethylene glycol (PEG-SSA) was conjugated with polyethylenimine(PEL). PEL is well known for a good endosomal escaping and DNA condensign agent. The positively charged syn-thetic fusogenic peptide, KALA was coated on the negatively charged PEG-g-PEI/DNA and PEI/DNA complexes. The KALA/PEI/ DNA complexes exhibited aggregation behavior at higher KALA coating amount with an effective diameter of around 1,000 nm. However, the LALA/PEG-g-PEI/DNA complexes were 100-300 nm in size with a surface zeta-potential (ζ)value of about +20mV. The conjugated PEG molecules suppressed any KALA-mediated inter-particle aggregation, and thereby improved the transfection efficiency, Consequently, the transfection efficiency of the KALA/PEG-g-PEI/DNA complexes was obtained by utilizing both the fusogenic activity of KALA and the steric repulsion effect of PEC.

• Applied Chemistry for Engineering
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• v.34 no.1
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• pp.1-8
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• 2023

Polyethylenimine (PEI) is a cationic polymer that can bind to negatively charged biomaterials such as nucleic acids through strong electrostatic interactions. Based on these properties, PEI has been used as an efficient drug delivery system for a long time. However, the strong cationic nature of PEI has the problem of causing cytotoxicity by non-specific interaction with anionic biological materials in the cells. In order to overcome these problems, many researchers have developed various types of biocompatible PEI-based materials. In this review, we would like to introduce the recent developments of functional PEI and their applications in biomedical research.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.660-662
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• 2010

To control replication of human cytomegalovirus (HCMV) effectively, inhibitors of peptide nucleic acids (PNA) with a gene delivery agent, PEI (polyethylenimine) against HCMV were applied. The transfection of these PNA inhibitors with PEI agent into host cells showed synergic inhibition effect of HCMV replication. These inhibition effect was confirmed by methods of RT-PCR, CPE, real-time-PCR, and Western blot.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.284-292
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• 2018

Receptor for advanced glycation end-products (RAGE) is overexpressed in various cancer cells. In this study, a RAGE-binding peptide (RBP) was conjugated to polyethylenimine (25 kDa, PEI). RBP-conjugated PEI (PEI-RBP) was characterized as a dual-functional reagent, a RAGE-mediated gene carrier and an anti-angiogenic reagent. As a gene carrier, PEI-RBP had higher transfection efficiency to the C6 glioblastoma cells than PEI. As an anti-angiogenic reagent, the pEmpty/PEI-RBP complex reduced RAGE expression on the surface of the C6 glioblastoma cells. Also, the complex reduced the VEGF expression and tube formation of endothelial cells. Therefore, PEI-RBP may be useful for development of glioblastoma therapy.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.425.1-425.1
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• 2002

Nanoparticles of polylactic acid (PLA) and polyethylenimine (PEI) as an effective gene delivery agent were prepared and characterized. As a model plamid DNA. PME185/$\beta$-gal. a mammalian expression vector. and fluorescence enhancing protein (pEGHP) were used. The effects of PEI type on the physical properties of nanoparticles and transfection efficiency were examined. (omitted)

• Archives of Pharmacal Research
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• v.28 no.11
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• pp.1302-1310
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• 2005

Glucosylated polyethylenimine (GPEI) was synthesized as a tumor-targeting gene carrier through facilitative glucose metabolism by tumor glucose transporter. Particle sizes of GPEI/DNA complex increased in proportion to glucose content of GPEI, whereas surface charge of the complex was not dependent on glucosylation, partially due to inefficient shielding of the short hydrophilic group introduced. GPEI with higher glucosylation (36 mol-$\%$) had no cytotoxic effect on cells even at polymer concentrations higher than 200 $\mu$g/mL. Compared to unglucosylated PEl. glucosylation induced less than one-order decrease of transfection efficiency. Transfection of GPEI/DNA complex into tumor cells possibly occurred through specific interaction between glucose-related cell receptors and glucose moiety of GPEI. Gamma imaging technique revealed GPEI/DNA complex was distributed in liver. spleen. and tumors.

• Bulletin of the Korean Chemical Society
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• v.28 no.1
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• pp.95-98
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• 2007

Polyethylenimine (PEI) has been widely investigated for delivery of DNA into cells. It was previously reported that there were at least two types of cytotoxicity in PEI-mediated gene delivery, immediate and delayed toxicities. PEI-mediated gene delivery protocols use net cationic complexes with an excess of PEI to maintain equilibrium between the complexed and dissociated forms in solution. In this study, toxicity of free PEI or PEI/ DNA complex was investigated. Human embryonic kidney 293 cells were incubated with free PEI or PEI/DNA complex for 4 hrs. Then, the cells were analyzed at 6, 24, 48, and 96 hrs after the incubation. In MTT assay, the viability of the cells incubated with PEI/DNA complex was continuously decreased with time, while that of the cells incubated with free PEI was not. On the contrary, the expression level of the luciferase gene increased gradually along with time. Release of DNAs from the complexes for transcription produces free PEIs in the cells. This process may proceed slowly due to high charge density of PEI and may be related to delayed toxicity. In addition, apoptotic cells were observed only in the cells incubated with the PEI/DNA complex from 24 hrs after the incubation. The results suggest that PEI/DNA complex contributes to the delayed toxicity by inducing apoptosis and that the delayed toxicity may be related to decomplexation of the complexes in the cells.

• Bulletin of the Korean Chemical Society
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• v.22 no.1
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• pp.46-52
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• 2001

To evaluate the non-ionic polymer, poly(ethylene glycol) (PEG), as a component in cationic copolymers for non-viral gene delivery systems, PEG was coupled to polyethylenimine (PEI). We present the effects of different degrees and shapes of pegylation of PEI on cytotoxicity, water solubility and transfection efficiency. This work reports the synthesis and characterization of a series of cationic copolymers on the basis of the conjugates of PEI with PEG. The modified molecules were significantly less toxic than the original polymer. Moreover, the chemical modification led to enhancement of their solubility. The comparison of pegylated PEIs with different degrees of derivation showed that all the polymers tested reached comparable levels of transgene expression to that of native PEI. As assessed by agarose gel electrophoresis, even highly substituted PEI derivatives were still able to form polyionic complexes with DNA. However, aside from an increase in solubility and retention of the ability to condense DNA, methoxy-PEG-modified PEIs resulted in a significant decrease in the transfection activity of the DNA complexes. In fact, the efficiency of the copolymer was compromised even at a low degree of modification suggesting that the PEG action resulting from its shape is important for efficient gene transfer. The mode of PEG grafting and the degree of modification influenced the transfection efficiency of PEI.

• Macromolecular Research
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• v.15 no.2
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• pp.100-108
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• 2007

Gene therapy has become a promising strategy for the treatment of genetically based diseases, such as cancer, which are currently considered incurable. A major obstacle in the field of cancer gene therapy is the development of a safe and efficient delivery system for therapeutic gene transfer. Non-viral vectors have attracted great interest, as they are simple to prepare, stable, easy to modify and relatively safe compared to viral vectors. In this review, an insight into the strategies developed for polyethylenimine (PEI)-based non-viral vectors has been provide, including improvement of the polyplex properties by incorporating hydrophilic spacer, poly(ethylene glycol) (PEG). Moreover, this review will summarize the strategies for the tumor targeting. Specifically, a targeted polymeric gene delivery system, PEI-g-PEG-RGD, will be introduced as an efficient gene delivery vector for tumor therapy, including its functional analysis both in vitro and in vivo.