• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2387-2392
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• 2009

A composite film of multi-walled carbon nanotube (MWCNT)/sol-gel-derived zinc oxide(ZnO)/Nafion has been utilized as an efficient immobilization matrix for the construction of a highly sensitive and stable tris(2,2'-bipyridyl) ruthenium(II) (Ru(${bpy)_3}^{2+})$ electrogenerated chemiluminescence (ECL) sensor. The electrochemical and ECL behaviors of Ru(${bpy)_3}^{2+})$ ion-exchanged into the composite film were strongly dependent upon the sol-gel preparation condition, the amount of MWCNT incorporated into the ZnO/Nafion composite film, and the buffer solution pH. The synergistic effect of MWCNTs and ZnO in the composite films increased not only the sensitivity but also the long-term stability of the ECL sensor. The present ECL sensor based on the MWCNT/ZnO/Nafion gave a linear response ($R^2$ = 0.999) for tripropylamine concentration from 500 nM to 1.0 mM with a remarkable detection limit (S/N = 3) of 15 nM. The present ECL sensor showed outstanding long-term stability (94% initial signal retained for 5 weeks). Since the present ECL sensor exhibits large response towards NADH, it could be applied as a transduction platform for the ECL biosensor in which the NADH is produced from the dehydrogenase-based enzymatic reaction in the presence of NA$D^+$ cofactor.

• Journal of the Korean Chemical Society
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• v.45 no.3
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• pp.223-229
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• 2001

A method for the determination of glucose in human whole blood by chemiluminescence method using a stopped flow injection system has been studied. The method is based on the differences in the chemiluminescence intensities of luminol due to the different amounts of hydrogen peroxide produced from the glucose oxidase catalyzed reaction. The enzyme reactor was prepared by immobilization of glucose oxidase on aminopropyl glass beads and the chemiluminescence from a flow cell was measured by means of an optical fiber bundle. In order to obtain the optimum experimental conditions, effects of pH for the chemiluminogenic solution and enzyme reactor, flow rate and temperature on the chemiluminescence intensity were investigated. The calibration curve obtained under optimum experimental conditions was linear over the range from $1.0{\times}10^{-1}$ mM to 7.0 mM and the detection limit was $6.0{\times}10^{-2}$ mM. The proposed method was applied to the determination of glucose in whole human blood sample and the results were compared with those obtained by an official method. The present method was also evaluated by the results of recovery experiments.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.04a
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• pp.99-101
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• 1998

1. Introduction : The conventional grafting polymerization technique requires chemically reactive groups on the surface as well as on the polymer chains. For this reason, a series of prefunctionalization steps are necessary for covalent grafting. The surface prefunctionalizational technique for grafting can be used to ionization radiation, UV, plasma, ion beam or chemical initiators. Of these techniques, radiation method is one of the useful methods because of uniform and rapid creation of active radical sites without catalytic contamination in grafted samples. If the diffusion of monomer into polymer is large enough to come to the inside of polymer substrate, a homogeneous and uniform grafting reaction can be carried out throughout the whole polymer substrate. Radiation-induced grafting method may attach specific functional moieties to a polymeric substrate, such as preirradiation and simultaneous irradiation. The former is irradiated at backbone polymer in vacuum or nitrogen gas and air, and then subsequent monomer grafting by trapped or peroxy radicals, while the latter is irradiated at backbone polymer in the presence of the monomer. Therefore, radiation-induced polymerization can be used to modification of the chemical and physical properties of the polymeric materials and has attracted considerable interest because it imparts desirable properties such as blood compatibility. membrane quality, ion excahnge, dyeability, protein adsorption, and immobilization of bioactive materials. Synthesizing biocompatible materials by radiation method such as preirradiation or simultaneous irradiation has often used $\gamma$-rays to graft hydrophilic monomers onto hydrophobic polymer substrates. In this work, in attempt to produce surfaces that show low levels of anti-fouling of bovine serum albumin(BSA) solutions, hydroxyethyl methacrylate(HEMA) was grafted polypropylene membrane surfaces by preirradiation technique. The anti-fouling effect of the polypropylene membrane after grafting was examined by permeation BSA solution.

• Korean Journal of Microbiology
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• v.36 no.2
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• pp.150-154
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• 2000

In order to increase biological activities of Co~nebacteriumpseudodipI~t~~eriticum W3712 which degrades achemical softener (organopolysiloxane), the cells were immobilized on four immobilizing carriers by physicaladsorption. The cells immobilized on bentonite had higher removal efficiency than those immobilized onthe other carriers, and physical adsorption of organopolysiloxane on bentonite was 62.5%. The immobilizedcells were produced by 16 ml of culture broth with 20 g of bentonite, and 100 ml of the standard wastewatercontaining 12.000 mgll COD," with organopolysiloxane was removed 95.0% by 10.0 g of the immobilizedcells treatment at room temperature for 10 days by static culture.y static culture.

• Bulletin of the Korean Chemical Society
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• v.25 no.8
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• pp.1195-1201
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• 2004

Tyrosinase was covalently immobilized on platinum electrode according to the method we developed for laccase (Bull. Korean Chem. Soc. 2002, 23(7), 385) and p-chlorophenol, p-cresol, and phenol could be detected with sensitivities of 334, 139 and 122 nA/ ${\mu}M$ and the detection limits of 1.0, 2.0, and 2.5 ${\mu}M$, respectively. The response time ($t_{90\%}$) is 3 seconds for p-chlorophenol, and 5 seconds for p-cresol and phenol. The optimal pHs of the sensor are in the range of 5.0- 6.0. This sensor can tolerate at least 500 times repeated injections of p-chlorophenol with retaining 80% of initial activity. In case of tyrosinase and laccase co immobilized platinum electrode, the sensitivities are 560 nA/ ${\mu}M$ for p-phenylenediamine (PPD) and 195 nA/ ${\mu}M$ for p-chlorophenol, respectively. The sensitivity of the bi-enzyme sensor for PPD increases 70% compared to that of only laccase immobilized one, but the sensitivity for p-chlorophenol decreases 40% compared to that of only tyrosinase immobilized one. The sensitivity increase for the bi-enzyme sensor for PPD can be ascribed to the additional catalytic function of the co-immobilized tyrosinase. The sensitivity decrease for p-chlorophenol can be explained by the “blocking effect” of the co-immobilized laccase, which hinders the mass transport through the immobilized layer. If PPD was detected with the electrode that had been used for p-chlorophenol, the sensitivity decreased 20% compared to that of the electrode that had been used only for PPD. Similarly, if p-chlorophenol was detected with PPD detected electrode, the sensitivity also decreased 20%. The substrate-induced conformation changes of the enzymes in a confined layer may be responsible for the phenomena.

• Bulletin of the Korean Chemical Society
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• v.28 no.5
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• pp.783-790
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• 2007

The immobilization of proteins and their molecular interactions on various polymer-modified glass substrates [i.e. 3-aminopropyltriethoxysilane (APTS), 3-glycidoxypropyltrimethoxysilane (GPTS), poly (ethylene glycol) diacrylate (PEG-DA), chitosan (CHI), glutaraldehyde (GA), 3-(trichlorosilyl)propyl methacrylate (TPM), 3'-mercaptopropyltrimethoxysilane (MPTMS), glycidyl methacrylate (GMA) and poly-l-lysine (PL).] for potential applications in a nanoarray protein chip at the single-molecule level was evaluated using prismtype dual-color total internal reflection fluorescence microscopy (dual-color TIRFM). A dual-color TIRF microscope, which contained two individual laser beams and a single high-sensitivity camera, was used for the rapid and simultaneous dual-color detection of the interactions and colocalization of different proteins labeled with different fluorescent dyes such as Alexa Fluor® 488, Qdot® 525 and Alexa Fluor® 633. Most of the polymer-modified glass substrates showed good stability and a relative high signal-to-noise (S/N) ratio over a 40-day period after making the substrates. The GPTS/CHI/GA-modified glass substrate showed a 13.5-56.3% higher relative S/N ratio than the other substrates. 1% Top-Block in 10 mM phosphate buffered saline (pH 7.4) showed a 99.2% increase in the blocking effect of non-specific adsorption. These results show that dual-color TIRFM is a powerful methodology for detecting proteins at the single-molecule level with potential applications in nanoarray chips or nano-biosensors.

• Clean Technology
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• v.20 no.1
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• pp.51-56
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• 2014

In this study, PSf-$Al(OH)_3$ beads were prepared by immobilizating aluminum hydroxide $Al(OH)_3$ with polysulfone (PSf). The removal experiments of the fluoride ions by PSf-$Al(OH)_3$ beads were conducted batchwise and the parameters such as pH, initial fluoride concentration, and coexisting ions were investigated. The maximum removal capacity obtained from Langmuir isotherm was 52.4 mg/g and the optimum pH region of fluoride ions was in the range of 4 to 10. The removal process of fluoride ions by PSf-$Al(OH)_3$ beads was found to be controlled by both external mass transfer at the earlier stage followed by internal diffusion at the later stage. The presence of coexisting anions such as $HCO_3{^-}$, $SO{_4}^{2-}$, $NO_3{^-}$, and $Cl^-$ had a negative effect on removal of fluoride ions by PSf-$Al(OH)_3$ beads.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.4
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• pp.278-284
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• 2015

In general, plant roots accumulate more heavy metals than the above ground organs such as leaf, stem, and fruit. This implies that root medicinal plants would be an issue with excessive heavy metal accumulation. Therefore, the current study was carried out to investigate the distribution of heavy metal (focused on Cd and Pb) concentrations in soils and medicinal plant roots grown in different region of Korea. Total 293 samples for each soil and plant were collected along the national wide. Soil pH, total and phytoavailable metal concentrations (1 M $NH_4NO_3$ extracted) in soils were determined and heavy metal concentrations in root of the medicinal plants were analyzed. Heavy metal concentrations of the soil samples studied were not exceeded standard limits legislated in 'Soil Environmental Conservation Act', except 2 samples for Cu. However, substantial amount of Cd was accumulated in medicinal plant roots with 29% samples exceeding the standard limit legislated in 'Pharmaceutical Affairs Act' while all plant samples were lower than the standard limit value for Pb. Also the current study demonstrated that cadmium concentrations in the roots were governed by the phytoavailable Cd in soils, which decreased as soil pH increased. From this result, application of heavy metal immobilization technique using a pH change-induced immobilizing agents can be suggested for safer root medicinal plant production.

• KSBB Journal
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• v.23 no.3
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• pp.263-270
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• 2008

A poly-(dimethylsiloxane) (PDMS) surface modified by the successive deposition of the polyelectrolytes, poly-(allylamine hydrochloride) (PAH), poly-(diallyldimethylammoniumchloride) (PDAC), poly-(4-ammonium styrenesulfonic acid) (PSS), and poly-(acrylic acid) (PAA), was presented for the application of selective cell immobilization. It is formed via electrostatic attraction between adjacent layers of opposite charge. The modified PDMS surface was examined using static contact angle measurements and fourier transform infrared (FT-IR) spectrophotometer. The wettability of the PDMS surface could be easily controlled and functionalized to be biocompatible through regulation of layer numbers. The modified PDMS surface provides appropriate environment for adhesion to cells, which is essential technology for cell patterning with high yield and viability in the patterning process. This method is reproducible, convenient, and rapid. It could be applied to the fabrication of biological sensing, patterning, microelectronics devices, screening system, and study of cell-surface interaction.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.472-478
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• 2023

In this study, the acetaldehyde removal characteristics of activated carbon (AC) for air purifier filters were investigated using metal catalysts-impregnation and functional group-modification method. The AC with a high specific surface area(1700 m²/g) and micropores was prepared by KOH activation of coconut charcoal and the efficiency of catalyst and functional group immobilization was examined by varying the drying conditions within the pores after immersion. The physical properties of the prepared activated carbon were analyzed by BET, ICP, EA, and FT-IR, and the acetaldehyde adsorption performances were investigated using gas chromatography (GC) at various impregnation and modified conditions. As the concentration of impregnation solution increased, the amount of impregnated metal catalysts increased, while the specific surface area showed a decreasing trend. The adsorption tests of the metal catalyst-impregnated and functional group-modified activated carbons revealed that excellent adsorption performance in compositions MgO10@AC, CaO10@AC, EU10@AC, and H-U3N1@AC, respectively. The MgO10@AC, which showed the highest adsorption performance, had a breakthrough time of 533.8 minutes and adsorption capacity of 57.4 mg/g for acetaldehyde adsorption. It was found that the nano-sized MgO catalyst on the activated carbon improved the adsorption performance by interacting with carbonyl groups of acetaldehyde.