• Korean Chemical Engineering Research
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• v.57 no.2
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• pp.232-238
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• 2019

Polyethylenimine-crosslinked chitin (PEI-chitin) was developed as a biosorbent to effectively remove dyestuffs from dye-containing wastewater. A representative reactive dye, Reactive Orange 16 (RO16) was used as a model dye. The effect of pH, isotherm, kinetic and desorption experiments were performed to evaluate the adsorption/desorption ability of PEI-chitin for RO16. As a result, the maximum adsorption capacity calculated by the Langmuir model was 266.3 mg/g at pH 2, and the time needed for adsorption equilibrium was evaluated to be about 20, 60, and 240 min for 50, 100, and 200 mg/L, respectively. The desorption experiments were carried out using various eluents such as ammonia/ethanol mixture, NaOH, $NaHCO_3$, and $Na_2CO_3$, and the highest desorption rate was 75.24% in the ammonia/ethanol mixture.

• Composites Research
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• v.36 no.5
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• pp.342-348
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• 2023

There has been increasing demand for real-time monitoring of body and ambient temperatures using wearable devices. Graphene-based thermistors have been developed for high-performance flexible temperature sensors. In this study, the temperature coefficient of resistance (TCR) of monolayer graphene was controlled by coating polyethylenimine (PEI) on graphene surfaces to enhance its temperature-sensing performances. Monolayer graphene grown by chemical vapor deposition (CVD) was wet-transferred onto a target substrate. To facilitate the interfacial doping by PEI, the hydrophobic graphene surface was altered to be hydrophilic by oxygen plasma treatments while minimizing defect generation. The effect of PEI doping on graphene was confirmed using a back-gated field-effect transistor (FET). The CVD-grown monolayer graphene coated with PEI exhibited an improved TCR of -0.49(±0.03) %/K in a temperature range of 30~50℃.

• Carbon letters
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• v.10 no.3
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• pp.221-224
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• 2009

In this work, the $CO_2$ adsorption behaviors of amine functionalized activated carbons (ACs) were investigated. The surface of ACs was modified with urea, melamine, diethylenetriamine (DETA), pentaethylenehexamine (PEHA), polyethylenimine (PEI), and 3-aminopropyl-triethoxysilane (ATPS). The various surface properties of amine functionalized ACs were characterized by Boehm's method, nitrogen full isotherms, XPS, and TGA analyses. The active ingredients impregnated on the ACs show significant influence on the adsorption for $CO_2$ and its volumes adsorbed on amine functionalized ACs are larger than that on the pristine ACs, which is due to the grafted amine groups of the AC surfaces.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.437-437
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• 2011

수열합성법에 의해 나노와이어를 합성하였다. 수직하고 장경비가 큰 나노와이어는 기존 Zinc nitrate와 HMTA를 각각 같은 몰 농도(0.015 mol/L)로 하고 이때 나노와이어의 밀도 조절 및 수직성장을 돕고 더 길게 자랄 수 있도록 polyethylenimine (PEI)를 포함하였으며, 이때 화학적으로 불안정한 seed layer 보호하기 위하여 증가 된 Ph 농도를 완화하기 위해 nitrate acid 를 포함한 반응 용액 내에서 생성되었다. 합성된 나노와이어는 지그재그 전극과 결합하여 리니어 모터를 통해 일정한 시간 주기로 일정한 압력을 가하여 얻은 압전특성을 관찰하고 분석하였다.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.06a
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• pp.93-104
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• 1997

The objective of this study is to develop a method to reduce arsenic concentrations in contaminated water. This work is also aimed at increasing the specificity of membrane separation processes. Arsenic in contaminated waters is often present in the form of negatively charged oxyanions. These are relatively small molecules which cannot be separated directly by ultrafiltration. Oxyanions can be captured by polyelectrolytes and separated by ultrafiltration. Results will be presented on the use of two polyelectrolytes; polyethylenimine (PEI) and poly-diallyl dimethyl ammonium chloride (DADMAC) at various feed concentrations. A semi-continuous process utilizing PEI in a circulation loop was tested. The restfits indicate that better than 99.6 % recovery (permeate concentration < 0.001 $\mu$g/L) can be achieved based on an initial arsenic concentration of 300 $\mu$g/L. The results indicate that this treatment method is suitable as a main treatment process for drinking water or a polishing step after arsenic precipitation.

• Bulletin of the Korean Chemical Society
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• v.26 no.8
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• pp.1209-1213
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• 2005

Nuclear membrane is one of the main barriers in intracellular delivery of genetic materials. The previous report showed that glucocorticoid receptor dilated the nuclear pore to 60 nm in the presence of a ligand. It was also suggested that the transport of genetic material to nucleus might be facilitated by glucocorticoid. In this study, the effect of glucocorticoid preincubation in the polymeric gene delivery was investigated. The cells were preincubated with dexamethasone, a potent glucocorticoid, and transfection assays were performed with polyethylenimine (PEI) and polyamidoamine (PAMAM) dendrimer. As a result, the transfection efficiency of PEI or PAMAM to the cells in the presence of dexamethasone was enhanced, compared to the cells without dexamethasone. This effect was not observed in the cells preincubated with cholesterol. The polymer/DNA complex was stable in the presence of dexamethasone. In addition, the cytotoxicities of the polymeric carriers to the cells were observed in the presence of dexamethasone. In conclusion, dexamethasone enhances the transfection efficiency of polymeric carriers and may be useful in the development of polymeric gene carriers.

• BMB Reports
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• v.33 no.6
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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).

• KSBB Journal
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• v.13 no.4
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• pp.337-342
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• 1998

Immunosensor for the determination of LDL(Low-Density Lipoprotein), a good indicator for the diagnosis of atherosclerosis and hypercholesterolemia, was developed by using quartz crystal microbalance(QCM). The immunosensor consists of flow-through cell, oscillating circuit, oscilloscope, and frequency counter. FIA(Flow Injection Analysis) was applied to the QCM system for the measurement of LDL in liquid phase. Antibody showing binding affinity against LDL was immobilized on the gold electrode of a quartz crystal by covalent coupling via polyethylenimine / glutaredehyde. LDL was injected and bound to the antibody immobilized on the QCM immunosensor. The response of the immunosensor (F0 - F1) was found to be proportional to the LDL concentration from 200 $\mu\textrm{g}$/ml to 800 $\mu\textrm{g}$/ml. Operational conditions for the operation of immunosensor were also investigated in terms of sensitivity and non-specific binding.

• Membrane Journal
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• v.23 no.4
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• pp.312-318
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• 2013

Poly vinylidene fluoride (PVDF) hollow fiber membranes were hydrophilized using polyethylenimine (PEI) and p-xylylene dichloride (XDC), and poly(vinyl alcohol) (PVA) and poly (acrylic acid -co- maleic acid) (PAM) mixed solutions by varying the concentration of PAM were coated onto PVDF membrane surface. The surface coating was verified by the observation of scanning electron microscope (SEM) and the permselective characteristcs of the resulting composite membranes were tested for 90 wt% aqueous ethanol solution by the pervaporation technique. The effects of the corsslinking agent concentraion, the temperature of feed solution, and the reaction temperature on the flux and separation factors were measured. Typically, the flux, $1,480g/m^2hr$ at the reaction temperature $100^{\circ}C$, PAM 3 wt%, feed temperature $70^{\circ}C$ was obtained, on the other hand, for the separation factor, ${\alpha}_{W/E}=82$ at the conditions of the reaction temperature $100^{\circ}C$, PAM 15 wt% and feed temperature $25^{\circ}C$ was shown.

• Biomolecules & Therapeutics
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• v.1 no.2
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• pp.188-195
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• 1993

In order to understand the machanism of action and regulation of ${\beta}$-adrenergic receptor in terms of molecular level, the purification of receptor protein has a fundamental importance. Moreover, species differences among avian, amphibian and mammalian ${\beta}$-adrenergic receptors make it more important to purify mammalian ${\beta}$-adrenergic receptor. Because ${\beta}$-adrenergic receptor is an integral membrane protein, it must be solubilized from the membrane for the purification. The purpose of the present study was to solubilize and characterize the mammalian $\beta$-adrenergic receptor from guinea pig lung in quantities by more efficient and practical method eventually to purify receptor. Guinea pig lung membrane preparation was solubilized by sequential treatment of buffers containing low and high concentration of digitonin which are 0.2 and 1.2% respectively. About 50% of the total receptor pool was released by this double extraction procedure. The $\beta$-adrenoceptors in the digitonin extract were identified using the ${\beta}$-adrenergic antagonist, (-)-[$^3H$]-dihydroalprenolol ([$^3H$]DHA). The solubilized receptor retained all of the essential characteristics of membrane-bound receptor, namely saturability; stereoselectivity; high affinity to ${\beta}$-adrenergic drugs. For the measurement of soluble receptor activity, Sephadex G-50 chromatography method has been widely used. Inspite of its accuracy and wide acceptance, this technique employed troublesome column work which required long time to assay the activity of receptor. We employed another methods to measure receptor activity. When using 0.5% polyethylenimine pretreated GF/B glass fiber filter, filtration technique could be used to measure soluble receptor activity. This technique enabled us to reduce the total amount of time to assay by a factor of 4 as well as to detect soluble receptor. In the present study, we could establish more efficient and practical solubilization method of mammalian $\beta$-adrenergic receptor. The rapidity and high yield of this solubilization scheme, together with the favorable recovery of the receptor activity, are significant steps toward the ultimate purification of the mammalian $\beta$-adrenergic receptor. The result of this study together with more convenient purification method could provide large amount of purified receptor with ease for various research purposes.