• Title/Summary/Keyword: polyethylenimine

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EBV-Based Plasmid Encoding HSV-TK for Cytocidal Gene Therapy (HSV-TK 유전자를 암호화하는 EBV 유래 플라스미드를 이용한 유전자 치료)

  • Oh, Sang-Taek;Min, Kyoung-Ah;Kim, Chong-Kook;Lee, Suk-Kyeong
    • Journal of Pharmaceutical Investigation
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    • v.33 no.4
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    • pp.267-272
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    • 2003
  • Herpes simplex virus (HSV) thymidine kinase (TK) has been widely used for suicidal gene therapy in combination with nucleoside analogs such as ganciclovir (GCV). The use of HSV-TK is limited due to the side effect of GCV at high concentrations. Previous studies showed that stable transfectants of mutant HSV-TK with enhanced affinity to GCV were killed at lower GCV concentrations. In this study, we tested whether mutant HSV-TK can provide enhanced suicidal effect when transiently transfected with Epstein-Barr virus (EBV)-based plasmid. EBV-based plasmid which contains OriP and EBNA-1 sequence is well known for a stable episomal maintenance in human cells. Optimal transfection condition was assessed for SNU-638 gastric cancer cell line using polyetylnimine (PEI). Maximum transfection efficiency was achieved when DNA:PEI was 1:3 (w/v). Cytotoxicities of mutant and wild type HSV-TK were compared before and after partially selecting transfected cells. The cells were sensitive to $100\;{\mu}g/ml$ hygromycin. Following GCV treatment, more cells were killed after hygromycin selection than before selection. The mutant HSV-TK showed enhanced cytotoxicity compared with the wild type HSV-TK. Our results suggest that the EBV-based plasmid encoding mutant HSV-TK may be useful to treat the diseases caused by uncontrolled cell proliferation such as cancer and rheumatoid arthritis.

Studies on the Polyethylenimine-Polymethylenepolyphenylene Isocyanate Backbone Chelating Resin Synthesis for the Trace Heavy Metals Enrichment and Analysis(II) : Rubeanic Acid Loaded Carboxymethylated Polyamine-Polyurea Resin (미량 중금속의 농축 및 정량을 위한 폴리에틸렌이민-폴리메틸렌폴리페닐렌 이소시안에이트에 토대한 킬레이트 수지의 합성에 관한 연구(II) : 루빈산이 결합된 카르복시메틸화된 폴리아민-폴리우레아 수지)

  • Chung, Yong Soon;Lee, Kang Woo;Hwang, Jongyoun;Lim, Kwang Soo
    • Analytical Science and Technology
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    • v.6 no.5
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    • pp.435-442
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    • 1993
  • Carboxymethylated polyamine-polyurea resin loaded with rubeanic acid (RCCPPI resin) was obtained by 1 step chemical reaction between chlorocarboxymethylated polyamine-polyurea(CCPPI) resin as matrix polymer and rebeanic acid. This resin was confirmed with infrared spectrometry, elemental analysis, and thermal analysis(DSC). The adsorption characteristics of the heavy metal's on the resin were studied by measuring distribution coefficient($K_d$) with changing pH of the solutions and frontal chromatography. The enrichment, recovery, and analysis of trace heavy metals, such as cadmium, cerium, copper, nikel, lead, and zinc, in the presence of high concentrations of sodium, calcium, and acetate salts was possible quantitatively by a column packed with the resin at each optimum pH. Preconcentration factors were more than 25. To elute the adsorbed heavy metals on the resin, 0.025M EDTA solution(pH 9.0) was used.

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Separation of Chromium(III) and Chromium(VI) by Carboxymethylated Polyamine-Polyurea Resin Column (카르복시메틸화된 폴리아민-폴리우레아 수지관에 의한 3가와 6가 크롬의 분리)

  • Chung, Yong Soon;Lee, Kang Woo;Hwang, Jong Youn;Lee, Yong Moon
    • Analytical Science and Technology
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    • v.7 no.2
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    • pp.205-211
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    • 1994
  • Acetic acid and succinic acid bonded polyamine-polyurea(CPPI and SAPPI) resins were synthesized from the reaction of polyethylenimine-polymethylenepolyphenylene isocyanate(PPI) resin as matrix polymer and chloroacetic acid and chlorosuccinic acid respectively. These resins were confirmed with infrared spectrometry and elemental analysis. The adsorption characteristics of the chromium(III) and dichromate(or chromate) ions on the resins were studied by measuring distribution coefficients($K_d$) with changing pH of the solution. It was thought that these ions were adsorbed by ion exchange mechanism. Chromium(III) and dichromate ion could be separated with stepwise elution method by changing pH of the eluent using SAPPI resin packed column($0.6cm(i.\;d.){\times}10cm(L.)$). Also, dichromate ion could be preconecntrated with CPPI resin column by a concentration factor of 50.

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Adsorption of Heavy Metals Cd, Cu and Zn on Peat (Peat에 의한 중금속(重金屬) Cd, Cu, Zn의 흡착(吸着))

  • Han, Kang-Wan;Choi, Hyun-Ok
    • Korean Journal of Environmental Agriculture
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    • v.11 no.3
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    • pp.195-200
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    • 1992
  • Heavy metal adsorption on peat was studied to examine the utilization of abundant natural resouces as pollution control. The smaller the peat particle size, the more the heavy metals studied were adsorbed. Adsorption of heavy metals on peat was greater in single metal solutions than in mixed solutions, and the order of adsorption amount on peat was Cu > Cd > Zn. The most effective pH range of the adsorption of Cd, Zn, and Cu was between 4 and 6. With increasing the concentration of heavy metals the amount of adsorption on peat was increased, but the adsorption ratio was decreased. The adsorption of heavy metals on peat was fitted to the Freundlich isotherm and peat was appeared to be an effective adsorbent of the heavy metals. The treatment of polyethyleneimine(PEI) on the peat surface effectively increased adsorption capacity of the heavy metals. Because of its higher energy content, the heavy metal adsorbed peat could be utilized as a energy source. After burning the peat, the reduced peat volume could be save the expenses for waste disposal.

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Inverted CdSe/ZnS Quantum Dots Light-Emitting Diode Using Low-Work Function Organic Material Polythylenimine Ethoylated

  • Kim, HongHee;Son, DongIck;Jin, ChangKyu;Hwang, DoKyung;Yoo, Tae-Hee;Park, CheolMin;Choi, Won Kook
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.246.1-246.1
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    • 2014
  • Over the past several years, colloidal core/shell type quantum dots lighting-emitting diodes (QDLEDs) have been extensively studied and developed for the future of optoelectronic applications. In the work, we fabricate an inverted CdSe/ZnS quantum dot (QD) based light-emitting diodes (QDLED). In order to reduce work function of indium tin oxide (ITO) electrode for inverted structure, a very thin (<10 nm) polyethylenimine ethoxylated (PEIE) is used as surface modifier[1] instead of conventional metal oxide electron injection layer. The PEIE layer substantially reduces the work function of ITO electrodes which is estimated to be 3.08 eV by ultraviolet photoemission spectroscopy (UPS). From transmission electron microscopy (TEM) study, CdSe/ZnS QDs are uniformly distributed and formed by a monolayer on PEIE layer. In this inverted QDLEDs, blend of poly (9,9-di-n-octyl-fluorene-alt-benzothiadiazolo) and poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] are used as hole transporting layer (HTL) to improve hole transporting property. At the operating voltage of 8 V, the QDLED device emitted spectrally orange color lights with high luminance up to 2450 cd/m2, and showed current efficacy of 0.6 cd/A, respectively.

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Carrier Transport of Quantum Dot LED with Low-Work Function PEIE Polymer

  • Lee, Kyu Seung;Son, Dong Ick;Son, Suyeon;Shin, Dong Heon;Bae, Sukang;Choi, Won Kook
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.432.2-432.2
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    • 2014
  • Recently, colloidal core/shell type quantum dots lighting-emitting diodes (QDLEDs) have been extensively studied and developed for the future of optoelectronic applications. In the work, we fabricate an inverted CdSe/ZnS quantum dot (QD) based light-emitting diodes (QDLED)[1]. In order to reduce work function of indium tin oxide (ITO) electrode for inverted structure, a very thin (<10 nm) polyethylenimine ethoxylated (PEIE) is used as surface modifier[2] instead of conventional metal oxide electron injection layer. The PEIE layer substantially reduces the work function of ITO electrodes which is estimated to be 3.08 eV by ultraviolet photoemission spectroscopy (UPS). From transmission electron microscopy (TEM) study, CdSe/ZnS QDs are uniformly distributed and formed by a monolayer on PEIE layer. In this inverted QD LED, two kinds of hybrid organic materials, [poly (9,9-di-n-octyl-fluorene-alt-benzothiadiazolo)(F8BT) + poly(N,N'-bis (4-butylphenyl)-N,N'-bis(phenyl)benzidine (poly-TPD)] and [4,4'-N,N'-dicarbazole-biphenyl (CBP) + poly-TPD], were adopted as hole transport layer having high highest occupied molecular orbital (HOMO) level for improving hole transport ability. At a low-operating voltage of 8 V, the device emits orange and red spectral radiation with high brightness up to 2450 and 1420 cd/m2, and luminance efficacy of 1.4 cd/A and 0.89 cd/A, respectively, at 7 V applied bias. Also, the carrier transport mechanisms for the QD LEDs are described by using several models to fit the experimental I-V data.

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Tunable Nanostructure of TiO2/Reduced Graphene Oxide Composite for High Photocatalysis

  • He, Di;Li, Yongli;Wang, Jinshu;Yang, Yilong;An, Qier
    • Applied Microscopy
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    • v.46 no.1
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    • pp.37-44
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    • 2016
  • In this study $TiO_2$/reduced graphene oxide ($TiO_2/rGO$) bipyramid with tunable nanostructure was fabricated by two-step solvothermal process and subsequent heat-treatment in air. The as-synthesized anatase $TiO_2$ nanocrystals possessed morphological bipyramid with exposed dominantly by (101) facets. Polyethylenimine was utilized during the combination of $TiO_2$ and graphene oxide (GO) to tune the surface charge, hindering the restack of graphene during solvothermal process and resulting in 1 to 5 layers of rGO wrapped on $TiO_2$ surface. After a further calcination, a portion of carbon quantum dots (CQDs) with a diameter about 2 nm were produced owing to the oxidizing and cutting of rGO on $TiO_2$. The as-prepared $TiO_2/rGO$ hybrid showed a highly photocatalytic activity, which is about 3.2 and 7.7 times enhancement for photodegradation of methyl orange with compared to pure $TiO_2$ and P25, respectively. We assume that the improvement of photocatalysis is attributed to the chemical bonding between rGO/CQDs and $TiO_2$ that accelerates photogenerated electron-hole pair separation, as well as enhances light harvest.

Evaluation of Thermally Oxidized Soybean Oil Using Carbon Nanotube Sensor (탄소나노튜브를 이용한 대두유의 가열산화 특성평가)

  • Lee, Eun-Ji;Lim, Seung-Yong;Fai, Vincent Lau Chun;Ju, Byeong-Kwon;Oh, Sang-Suk
    • Korean Journal of Food Science and Technology
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    • v.44 no.4
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    • pp.472-477
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    • 2012
  • As people are being exposed to many types of fast food, rancid oil is a factor affecting public health. Monitoring of rancidity in frying oils needs to be done adequately. The chemical methods that are currently used require long periods of time and expertise. The development of a device that quickly and easily measures rancidity would be helpful to manage rancidity in frying oils adequately. Due to the fact that carbon nanotube (CNT) is sensitive to acid value, we used CNT as a sensing material for detecting oil rancidity. Polyethylenimine (PEI) was coated on CNT for stable measurements. Experiments were conducted at $100^{\circ}C$ after samples were cooled from $180^{\circ}C$. The results showed a strong correlation between acid values and resistances using CNT sensors. As the acid value of oils increased, the resistance of CNT sensors increased. Development of sensors using CNT may make it possible to determine the rancidity of frying oils in real-time and on site.

Preparation of Poly(ethylenimine) Anionic Exchnage Membrane Impregnated in Porous Polyethylene Membranes (다공성 폴리에틸렌 막에 폴리에틸렌이민을 함침 시킨 음이온교환막의 제조 연구)

  • Park, Chan-Jong;Kim, Il-Hyung;Kim, Sung-Pyo;Lee, Hak-Min;Cheong, Seong-Ihl;Choi, Ho-Sang;Rhim, Ji-Won
    • Membrane Journal
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    • v.21 no.1
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    • pp.91-97
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    • 2011
  • In this study, the anionic exchange membranes were prepared through the impregnation of polyethylenimine (PEI) into porous polyethylene (PE) separator and then crosslinking with isophrhaloyl dichloride (IPC). To characterize the resulting membranes, the contact angles, FT-IR, ion exchnage capacity and ion conductivity were measured. The amide group is produced the reaction between amines in PEI and -COCl in IPC. In case of ion exchange capacity, 1.96 meq./g dry membrane at the reaction time, 30 sec was decreased to 1.14 meq./g dry membrane at 600 sec reaction time. The ion conductivity, $9.15{\times}10^{-2}S/cm$ at 30 sec reaction time, was obtained.

Nickel Ion Adsorption Behavior of Ceriporia lacerata Isolated from Mine Tailings in Korea

  • Kim, HaeWon;Lim, Jeong-Muk;Oh, Sae-Gang;Kamala-Kannan, Seralathan;Cho, Min;Oh, Byung-Taek
    • Journal of Soil and Groundwater Environment
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    • v.20 no.2
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    • pp.22-31
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    • 2015
  • In the present study, surface of laccase producing Ceriporia lacerata was modified using 4-bromobutyryl chloride and polyethylenimine. The modified biomass was freeze dried and utilized as a biosorbent for the removal of Ni(II) from aqueous solution. The physicochemical properties of the biosorbent were analyzed using scanning electron microscopy and Fourier transform infrared spectroscopy. Batch experiments were carried out as a function of contact time (0-60 min), pH (2 to 8), adsorbent dosage (25-150 mg), and initial Ni(II) concentration (25-125 mg/L). The results indicate that surface modified biosorbent effectively adsorbed (9.5 mg/0.1 g biomass) Ni(II) present in the solution. The equilibrium adsorption data were modeled with different kinetic and isotherm models. The Ni(II) adsorption followed pseudo-first-order kinetics (R2 = 0.998) and Langmuir isotherm (R2 = 0.994) model. Hydroxyl and carbonyl functional groups present in biomass play a major role in the adsorption of Ni(II). The adsorbed Ni(II) from the biosorbent was successfully desorbed (85%) by 1M HCl. The results of the study indicate that the surface modified C. lacerate biomass could be used for the treatment of Ni(II) contaminated ground waters.