• Journal of Microbiology and Biotechnology
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• v.19 no.8
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• pp.781-786
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• 2009

Small interfering synthetic double-stranded RNA (siRNA) was applied to suppress the expression of the human cytotoxic-T-Iymphocyte antigen 4-immunoglobulin (hCTLA4Ig) gene transformed in transgenic rice cell cultures. The sequence of the 21-nucleotide siRNA was deliberately designed and synthesized with overhangs to inactivate the expression of hCTLA4Ig. The chemically synthesized siRNA duplex was combined with polyethyleneimine (PEl) at a mass ratio of 1:10 (0.33 ${\mu}g$ siRNA:3.3 ${\mu}g$ PEl) to produce complexes. The siRNA complexes (siRNA+PEI) were labeled with Cy3 in order to subsequently confirm the delivery by fluorescent microscopy. In addition, the cells were treated with sonoporation at 40 kHz and 419W for 90 s to improve the delivery. The siRNA complexes alone inhibited the expression of hCTLA4Ig to 45% compared with control. The siRNA complexes delivered with sonoporation downregulated the production of hCTLA4Ig to 73%. Therefore, we concluded that the delivery of siRNA complexes into plant cells could be enhanced successfully by sonoporation.

• Journal of Microbiology and Biotechnology
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• v.19 no.11
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• pp.1490-1495
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• 2009

The development of nanotechnology has penetrated the fields of biology and medicine, resulting in remarkable applications for tissue regeneration. In order to apply this technology to tissue engineering, we have developed nano-scaled 3D scaffolds consisting of growth factor-loaded heparin/poly(l-lysine) nanoparticles (NPs) attached to the surface of polymeric micro spheres via polyionic complex methods. Growth factor-loaded NPs were simply produced as polyelectrolyte complexes with diameters of 100-200 nm. They were then coated onto positively charged poly(lactic-co-glycolic acid) (PLGA) pretreated with polyethyleneimine to enable cell adhesion, proliferation, and stimulation of neurite outgrowth. Propidium iodide staining and $\beta$-tubulin analysis revealed that neuronal PC12 cells proliferated extensively, expressed significant amounts of b-tubulin, and showed well-structured neurite outgrowth on polymeric microspheres by stimulation with growth factors. These results suggest that cellular adhesion and biological functionality on prepared PLGA microspheres enabled terminal differentiation of neuronal cells.

• Macromolecular Research
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• v.17 no.1
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• pp.19-25
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• 2009

In order to enhance the gene delivery efficiency and decrease the cytotoxicity of polyplexes, we synthesized Solutol-g-PEI by conjugating polyethyleneimine (PEI) to Solutol (polyoxyethylene (10) stearate), and evaluated its efficiency as a possible nonviral gene carrier candidate. Structural analysis of synthesized polymer was performed by using $^1H$-NMR. Gel retardation assay, particle sizes and zeta potential measurement confirmed that the new gene carrier formed a compact complex with plasmid DNA. The complexes were smaller than 150 nm, which implicated its potential for intracellular delivery. It showed lower cytotoxicity in three different cell lines (Hela, MCF-7, and HepG2) than PEI 25 kDa. pGL3-lus was used as a reporter gene, and the transfection efficiency was in vitro measured in Hela cells. Solutol-g-PEI showed much higher transfection efficiency than unmodified PEI 25 kDa.

• Polymer(Korea)
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• v.35 no.2
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• pp.161-165
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• 2011

This study is related to the preparation of biocompatible gold nanoparticles (AuNPs) which are stable in aqueous solutions for a long time. Ultrasmall polyethyleneimine (PEI)-capped AuNPs (PEI-AuNPs) with limited agglomeration were prepared in aqueous solutions at room temperature, which were based on the roles of PEI as a reductant and a stabilizer. PEI-AuNPs with an average size of 8~12 nm formed highly stable nanocolloids with an average hydrodynamic cluster size of around 50 nm in aqueous media. At a low concentration of metal precursor hydrogen tetrachloroaurate (III), the particle size was reduced noticeably. The typical peaks of gold were observed in the X-ray diffraction pattern of AuNPs. The cell viability of 98% was obtained in the case of PEI-AuNPs, while PEI was cytotoxic. The PEI-AuNP is considered to be a potential candidate as a contrast agent for computed tomography.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.258-263
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• 2017

In this study, we synthesized biocatalyst consisting of glucose oxidase (GOx), polyethyleneimine (PEI) and carbon nanotube (CNT) with addition of p-benzoquinone (BQ) that was considered anodic catalysts of enzymatic biofuel cell (EBC). For doing this, PEI/CNT supporter was bonded with BQ by physical entrapping method stemmed from electrostatic attractive force ([BQ/PEI]/CNT). In turn, GOx moiety was further immobilized on the [BQ/PEI]/CNT to form GOx/[BQ/PEI]/CNT catalyst. This catalyst has a special advantage in that the BQ that has been usually dissolved into electrolyte was immobilized on supporter. According to the electrochemical analysis, maximum current density of the GOx/[BQ/PEI]/CNT catalyst was 1.9 fold better than that of the catalyst that did not entrap BQ with the value of $34.16{\mu}A/cm^2$, verifying that catalytic activity of the catalyst was enhanced by adoption of BQ. Also, when it was used as anodic catalyst of the EBC, its maximum power density was 1.2 fold better than that of EBC using the catalyst that did not entrap BQ with the value of $0.91mW/cm^2$. Based on such results, it turned out that the GOx/[BQ/PEI]/CNT catalyst was promising and viable as anodic catalyst of EBC.

• Applied Chemistry for Engineering
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• v.22 no.6
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• pp.599-604
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• 2011

In this study, we investigated the efficacy of ${\beta}$-cyclodextrin (${\beta}CD$) hydrorogel containing silk fibroin (SF) on healing burnt wound. Tosyl ${\beta}CD$ was conjugated to polyethyleneimine (PEI) using epichlorohydrin (EPI) as a cross-linker. The ${\beta}CD/PEI/SF$ hydrogel was applied on the back of mouse and then the efficacy of hydrogel was compared with both positive control group and negative control group. There was no wound healing efficacy showed neither in the drug loaded ${\beta}CD/PEI/SF$ hydrogel group nor in the drug unloaded ${\beta}CD/PEI/SF$ hydrogel group. On the other hand, in the positive control group, a significant reduction of the wound size after the usage of OTC hydrorogel was obtained. The burn-healing histological result showed a similar phenomenon. After hematoxylin-eosin staining the skin induced by burning, and the epithelial growth observed in the dermis, the efficacy of ${\beta}CD/PEI/SF$ hydrogel in healing burnt wound could not be clearly identified.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.83-89
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• 2022

Since the pandemic of COVID-19, active investigation to develop immunity to infectious disease by delivering nucleic acids has been proceeded. Particularly, many studies have been conducted on non-viral vector as several vital side-effects which were found on nucleic acid delivery system using viral vectors. In this study, we have developed plasmid DNA (pDNA) loaded-hyaluronic acid derivative (HA) coated-polyethyleneimine (PEI) based polyplex for enhanced nucleic acid delivery efficiency. We have optimized the ratio of pDNA : PEI : HA by measuring size and protein transcription efficiency. The final product, polyplex-HA, was characterized through measuring size, zeta-potential and TEM image. Intracellular uptake and protein transcription efficiency were compared to commercially available transfection reagent, lipofectamine, through fluorescence image and flow cytometry. In conclusion, polyplex-HA presents a novel gene delivery system for efficient and stable protein transcription since it is available for delivering various genetic materials and has less immunoreactivity.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.693-697
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• 2016

In this study, we fabricated the catalysts for enzymatic biofuel cell anode with carbon nanotube (CNT), glucose oxidase (GOx) and various molecular weights branched poly(ethyleneimine)(bPEI) and terephthalaldehyde (TPA) as cross-linker. In case of GOx/bPEI/CNT using only physical entrapments for immobilization, the molecular weights of bPEI didn't affect to electrochemical performances and long term stability. but that of the catalysts cross linked via TPA (TPA[GOx/bPEI/CNT]) improved and the mass transfer of glucose to FAD was interrupted as increasing of the bPEI's molecular weights. Furthermore, it was confirmed that the optimum molecular weight of PEI for TPA [GOx/bPEI/CNT]) structure is 750k that showed marvelous high performance (maximum power density of $0.995mW{\cdot}cm^{-2}$).

• Journal of Korean Society of Environmental Engineers
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• v.37 no.3
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• pp.175-181
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• 2015

Activated carbon impregnated with polyethyleneimine (PEI) was evaluated as a functionalized adsorbent for $CO_2$ capture. The $CO_2$ adsorption characteristics of the adsorbents was undertaken using GC/TCD, BET surface area and FT-IR. A series of adsorbents were synthesized by impregnating 10, 30, 50 wt% of PEI on activated carbons and were investigated $CO_2$ adsorption capacity at high and low adsorption temperature. The $CO_2$ adsorption capacity at $20^{\circ}C$ and $100^{\circ}C$ was as follow: AC > PEI(10)-AC > PEI(30)-AC > PEI(50)-AC at $20^{\circ}C$ and PEI(10)-AC > PEI(30)-AC > PEI(50)-AC > AC at $100^{\circ}C$. Adsorption capacities of amine functionalized AC was lager than virgin AC at high temperature due to chemisorption by amino-group content. From the results, the PEI(10)-AC showed one of the most promising adsorbents for $CO_2$ capture from flue gas at high temperature.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.802-807
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• 2015

In this study, we synthesized a new biocatalyst consisting of glucose oxidase (GOx), polyethyleneimine (PEI) and carbon nanotube (CNT) with addition of terephthalaldehyde (TPA) (TPA/GOx/PEI/CNT) for fabrication of glucose sensor that shows improved sensing ability and stability compared with that using other biocatalysts. Main bonding of the new TPA/GOx/PEI/CNT catalyst is formed by Aldol condensation reaction of functional end groups between GOx/PEI and TPA. Such formed bonding structure promotes oxidation reaction of glucose. Catalytic activity of TPA/GOx/PEI/CNT is evaluated quantitatively by electrochemical measurements. As a result of that, large sensitivity value of $41{\mu}Acm^{-2}mM^{-1}$ is gained. Regarding biosensor stability of TPA/GOx/PEI/CNT catalyst, covalent bonding formed between GOx/PEI and TPA prevents GOx molecules from becoming leaching-out and contributes improvement in biosensor stability. With estimation of the biosensor stability, it is found that the TPA/GOx/PEI/CNT catalyst keeps 94.6% of its initial activity even after three weeks.