• 한국응용과학기술학회지
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• 제32권2호
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• pp.202-214
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• 2015

Stimuli-responsive biomaterials that alter their function through sensing local molecular cues may enable technological advances in the fields of drug delivery, gene delivery, actuators, biosensors, and tissue engineering. In this research, pH-responsive hydrogel which is comprised of dimethylaminoethyl methacylate (DMAEMA) and 2-hydroxyethyl methacrylate (HEMA) was synthesized for the effective delivery of doxorubicin (Dox) to breast cancer cells. Cancer and tumor tissues show a lower extracellular pH than normal tissues. DMAEMA/HEMA hydrogels showed significant sensitivity by small pH changes and each formulation of hydrogels was examined by scanning electron microscopy, mechanical test, equilibrium mass swelling, controlled Dox release, and cytotoxicity. High swelling ratios and Dox release were obtained at low pH buffer condition, low cross-linker concentration, and high content of DMAEMA. Dox release was accelerated to 67.3% at pH 5.5 for 6-h incubation at $37^{\circ}C$, while it was limited to 13.8% at pH7.4 at the same time and temperature. Cell toxicity results to breast cancer cells indicate that pH-responsive DMAEMA/HEMA hydrogels may be used as an efficient matrix for anti-cancer drug delivery with various transporting manners. Also, pH-responsive DMAEMA/HEMA hydrogels may be useful in therapeutic treatment which is required a triggered release at low pH range such as gene delivery, ischemia, and diabetic ketoacidosis.

• 폴리머
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• 제30권4호
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• pp.286-292
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• 2006

Super water-absorbent resins were prepared by inverse suspension copolymerization of sodium acrylate, acrylamide and 2-hydroxyethyl acrylate using N, N'-methylene-bis-acrylamide as cross-linker. For the suspension copolymerization, monohexadecyl phosphate was employed as the dispersing agent, cyclohexane as the dispersing medium and potassium persulfate as the initiator. The dependence of water-absorption capacity on the amount of crosslinking agent, oil/water ratio, degree of neutralization and the composition of the copolymer were systematically investigated. Furthermore, the swelling kinetics of the super water-absorbent copolymer was carried out. The absorption of the resins is more than 1800 g/g for deionized water and 100 g/g for 0.9% NaCl solution, respectively. The copolymers showed an increased salt resistance and enhanced water retention of soil.

• 폴리머
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• 제37권3호
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• pp.288-293
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• 2013

A group of molecularly imprinted polymers (MIPs) with specific recognition for chiral (S)-ibuprofen were successfully prepared based on hydrogen bonds, utilizing ${\alpha}$-methacrylic acid as a functional monomer. The IR analysis of MIPs showed that the blue- and red-shifted hydrogen bonds were formed between templates and functional monomers in the process of self-assembly imprinting and re-recognition, respectively. According to UV-Vis analysis, we found that the ratio of host-guest complexes between template molecule and functional monomer was 1:1. The effect of cross-linker's quantity on the polymerization was studied by transmission electron microscope (TEM). The adsorption selectivity experiments indicated that MIPs exhibited higher selectivity to (S)-ibuprofen than those to ketoprofen and (R)-ibuprofen, (S)-ibuprofen's structural analogs.

• 통합자연과학논문집
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• 제9권4호
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• pp.249-254
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• 2016

This study evaluated the physical and optical characteristics of hydrophilic ophthalmic polymer with addition of 2-methacryloyloxyethyl phosphorylcholine in the basic hydrogel ophthalmic lens material, and in particular, the utility of 2-methacryloyloxyethyl phosphorylcholine as an ophthalmic contact lens material for ophthalmologic devices was investigated. In this study 2-methacryloyloxyethyl phosphorylcholine were used as additives. For the preparation of hydrogel lens 2-hydroxyethyl methacrylate, methyl methacrylate, acrylic acid and a cross-linker EGDMA were copolymerized in the presence of AIBN as an initiator. The physical properties of the produced polymers were measured as followings. The refractive index of 1.433~1.393, water content of 35.95~53.16%, contact angle of $70.6{\sim}51.24^{\circ}$, UVB transmittance of 81.2~82.4%, UV-B transmittance of 81.2~82.4% and visible transmittance of 91.4~92.2% were obtained. Also, in case of protein absorption, the measurement showed that absorbance of Reference and MPC-10 sample was 0.2598 and 0.2250 respectively. Based on the results of this study, ophthalmic lens material containing 2-methacryloyloxyethyl phosphorylcholine is expected to be used usefully as a material for high wettability and inhibitor of protein adsorption for ophthalmic hydrogel lens.

• 생명과학회지
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• 제9권1호
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• pp.76-83
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• 1999

Endoplasmic reticulum (ER)내에 단백질의 folding과 안정화에 관여하는 단백질을 molecular cha-perone이라고 한다. GRP94 역시 ER내에 존재하는 molecular chaperone으로 알려지고 있지만 갑상선세포에서 단백질의 folding에 관여한다는 증거는 아직 불충분하다. 본 설험은 molecular chaperone을 세포내에서 overexpression시킬 수 있는 system을 확립하였다. 그 중에서 GRP94가 단백질의 folding에 직접적으로 관여한다는 증거를 얻기 위하여, endogenous GRP94를 code한 cDNA를 overexpression vector에 의해서 forced expression시킴으로 신생thyroglobulin의 folding에 직접적으로 관여하는 증거를 immun-oprecipitation으로 증명하였다.

• 센서학회지
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• 제21권5호
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• pp.345-351
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• 2012

Biomimetic terpene sensors which have high sensitivity and stability have been fabricated using moleculary imprinted polymer (MIP) technology. Since it is impossible to make a resistive type sensor due to the high resistance of MIP, we improved the sensor by adding conductive polymers. We investigated the sensitivity of resistive type sensors with nano particles depending on the amount of conductive polymers. The MIP membrane contained the methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross linker, which formed specific cavities originated by the target terpene molecules. The mixture of MIP and the conductive polymer was coated on the patterns of interdigit electrodes on the alumina substrate. The fabricated sensors showed their highest specific sensitivities exposed to 500 ppm target gases : limonene 0.055 at 40% of amount of conductive polymers and geraniol $5.84{\times}10^{-4}$ at 20% of amount of conductive polymers. In conclusion, we found that the terpene sensors are affected by the target molecules, functional monomers and the conductive polymers.

• Advances in environmental research
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• 제2권4호
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• pp.309-321
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• 2013

High AA new high capacity sorbent for preconcentration and determination of nickel in environmental samples was synthesized. The sorbent was synthesized by copolymerization of allyl glaycidyl ether / imminodiacetic acid with N,N-dimethylacrylamide as functional monomers in the presence of N,N-bismethylenacryl amid as cross linker and characterized by Fourier transform infra red spectroscopy, elemental analysis, thermogravimetric analysis and scanning electron microscopy. A recovery of 93.6% was obtained for the metal ion with 0.1 M, sulfuric acid as the eluting agent. The sorption capacity of the functionalized sorbent was 55.9 $mgg^{-1}$. The equilibrium sorption data of Ni(II) on polymeric sorbent were analyzed using Langmuir, Freundlich, Temkin and Redlich.Peterson models. Based on equilibrium adsorption data the Langmuir, Freundlich and Temkin constants were determined 0.87 (L mg-1), 25.87 ($mgg^{-1}$) $(Lmg^{-1})^{1/n}$ and 171.4 ($Jmol^{-1}$) respectively at pH 4.5 and $20^{\circ}C$.

• 대한화학회지
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• 제53권3호
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• pp.340-344
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• 2009

Phosphonitrillic chroride cyclic trimer 화합물을 $200{\sim}300\;{^{\circ}C}$ 하에 개환중합하여 선상 고분자를 얻 은 후 Grignard 시약 ($CH_2$=CH-MgBr)을 천천히 가하여 vinyl 기를 포함하는 polyphosphazene을 합성하였 으며, 이 폴리머를 HEMA(2-hydroxyethyl methacrylate)와 반응시켜 HEMA/vinyl-substituted polyphosphazene 을 얻었다. 이 고분자를 AIBN (azobisisobutyronitrile) 개시제 존재 하에서 교차결합제로 EGDMA(ethylene glycol dimethacrylate) 그리고 NVP (N-vinyl-pyrrolidone)을 혼합하여 공중합 시켰다. 얻어진 공중합체에 대한 측정 결과 산소투과율 (Dk/t)은 88로 측정되었으며, 함수율은 30.89% 그리고 가시광선 투과율은 87%로 나타났다. 이 자료로부터 이 공중합체가 우수한 콘택트렌즈 재료임을 발견하였다.

• 통합자연과학논문집
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• 제9권1호
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• pp.16-22
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• 2016

The optical and physical and characteristics of hydrogel ophthalmic lens polymerized with addition of 2,6-difluoropyridine, SiPc(silicon 2,9,16,23-tetra-tert-butyl-29H31H-phthalocyanine dihydroxide) and nanodiamond in the basic hydrogel material were evaluated. In particular, the utility of 2,6-difluoropyridine, SiPc and nanodiamond as a hydrogel ophthalmic lens material was investigated. 2,6-difluoropyridine, SiPc and nanodiamond were used as additives. And also, 2-hydroxyethyl methacrylate, acrylic acid, methyl methacrylate and a cross-linker EGDMA were copolymerized in the presence of AIBN as an initiator. The refractive index of 1.4348~1.4361, water content of 33.30~34.02%, UV-B transmittance of 4.77~67.50%, UV-A transmittance of 1.45~89.19% and visible transmittance of 32.12~92.21% were obtained. The results of hydrogel lens containing 2,6-difluoropyridine (add 5%) showed antibiosis for staphylococcus aureus. The produced copolymer is suitable for hydrogel soft ophthalmic lenses with antibiotic and anti-UV effect.

• Journal of Microbiology and Biotechnology
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• 제29권7호
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• pp.1078-1082
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• 2019

Poly-${\gamma}$-glutamate (${\gamma}$-PGA) has various applications due to its desirable characteristics in terms of safety and biodegradability. Previous studies have been conducted on ${\gamma}$-PGA hydrogels produced by ${\gamma}$-ray irradiation, but these hydrogels have proved unstable in solutions. This study was conducted to enable the ${\gamma}$-PGA hydrogel to maintain a stable form in solutions. The ${\gamma}$-PGA mixture for UV-irradiation was prepared with a cross-linker (N,N,N-trimethyl-3-[(2-methylacryloyl)amino]propan-1-aminium). Both ${\gamma}$-PGA hydrogels' characteristics, including stability in solutions, were examined. The UV-irradiated ${\gamma}$-PGA hydrogel maintained a stable form during the nine weeks of the study, but the ${\gamma}$-ray irradiated hydrogel dissolved after one week.