• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1100-1106
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• 2008

In this study, we presented rapid and simple fabrication method of functionalized surface on various substrates as a universal platform for the selective immobilization of cells. The functionalized surface was achieved by using deposition of polyelectrolyte such as poly(allyamine hydrochloride) (PAH), poly(diallyldimethyl ammonium chloride) (PDAC), poly(4-ammonium styrene sulfonic acid) (PSS), poly(acrylic acid) (PAA) and fabrication of poly(ethylene glycol) (PEG) microstructure through micro-molding in capillaries (MIMIC) technique on each glass, poly(methyl methacrylate) (PMMA), polystyrene (PS) and poly(dimethyl siloxane) (PDMS) substrate. The polyelectrolyte multilayer provides adhesion force via strong electrostatic attraction between cell and surface. On the other hand, PEG microstructures also lead to prevent non-specific binding of cells because of physical and biological barrier. The characteristic of each modified surface was examined by using static contact angle measurement. The modified surface onto several substrates provides appropriate environment for cellular adhesion, which is essential technology for cell patterning with high yield and viability in the micropatterning technology. The proposed method is reproducible, convenient and rapid. In addition, the fabrication process is environmentally friendly process due to the no use of harsh solvent. It can be applied to the fabrication of biological sensor, biomolecules patterning, microelectronics devices, screening system, and study of cell-surface interaction.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.468-472
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• 2003

Recently, genetic engineering techniques have been used to display various heterologous peptides and proteins (enzyme, antibody, antigen, receptor and fluorescence protein, etc.) on the yeast cell surface. Living cells displaying various enzymes on their surface could be used repeatedly as 'whole cell biocatalysts' like immobilized enzymes. We constructed a yeast based whole cell biocatalyst displaying T. reesei cellobiohydrolase I (CBH I ) on the cell surface and endowed the yeast-cells with the ability to degrade cellulose. By using a cell surface engineering system based on ${\alpha}-agglutinin,$ CBH I was displayed on the cell surface as a fusion protein containing the N-terminal leader peptide encoding a Gly-Ser linker and the $Xpress^{TM}$ epitope. Localization of the fusion protein on the cell surface was confirmed by confocal microscopy. In this study, we report on the genetic immobilization of T. reesei CBH I on the S. cerevisiae and hydrolytic activity of cell surface displayed CBH I.

• Journal of Microbiology and Biotechnology
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• v.17 no.9
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• pp.1533-1537
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• 2007

In this study, in order to develop a continuous production process of lactosucrose in a packed-bed reactor, Sterigmatomyces elviae ATCC 18894 was selected and mutated. The mutant strain of S. elviae showed 54.3% higher lactosucrose production than the wild type. Reaction conditions such as temperature, pH, substrate concentration and flow rate were also optimized. Under optimized reaction conditions ($50^{\circ}C$, pH 6.0, 25% sucrose and 25% lactose as substrate, flow rate 1.2 ml/min), the maximum concentration of lactosucrose (192 g/l) was obtained. In a packed-bed reactor, continuous production of lactosucrose was performed using S. elviae mutant immobilized in calcium alginate, and about 180 g/l of lactosucrose production was achieved for 48 days.

• KSBB Journal
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• v.15 no.5
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• pp.497-500
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• 2000

Liposomes and proteoliposomes, artificial membranes, can interact with many solutes, such as drugs, peptides and proteins. The immobilization of (prot대)liposomes as supramolecular aggregates on gold surfaces have potential applications in nano and biosensor technology. We demonstrated a quartz crystal analyzer (QCA) based method to monitor the construction of multi-layers of unilamellar liposomes based on avidin-biotin binding on gold surfaces using a quartz crystal microbalance (QCM). Thus, the QCA provides an on line and efficient method of detecting the construction of protein membranes, which has applications in biosensing systems.

• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.48-56
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• 2018

A potassium copper hexacyanoferrate (KCuHCF) embedded magnetic hydrogel bead (HCF-Mbead) was synthesized via a facile double crosslinking methods of $Fe^{3+}$ ionic binding and freeze-thaw for effective $Cs^+$ removal. The HCF-Mbead had a hierarchical porous structure facilitating fast access of $Cs^+$ ions to embedded active sites. The adsorbent showed enhanced $Cs^+$ removal properties in terms of capacity (69.2 mg/g), selectivity ($K_d=4{\times}10^4mL/g$, 1 ppm $Cs^+$ in seawater) and stability (>99.5% removal in pH 3~11) with rapid magnetic separation. This study further opens the possibility to develop an efficient material that links the integration of adsorption and recovery.

• KSBB Journal
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• v.23 no.4
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• pp.350-354
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• 2008

Magnetically separable immobilized trypsin was developed and their biocatalytic activity was evaluated for the different immobilization media. The activity, recyclability, pH effect, and stability of immobilized enzymes were evaluated for the different supporting media. The biocatalytic activity of immobilized trypsin was highest with magnetically separable polyaniline (PAMP), and Vm and Km of PAMP were 0.169 mM/min and 0.263 mM respectively. With increasedpH, the biocatalytic activity increased for all supporting materials used. Immobilized enzymes were recycled and recycle activities were over 90% of their original activity after ten times reuse. The operational stabilities of enzymes were greatly improved with enzyme immobilization.

• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.672-678
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• 2006

A new approach to fabricate an enzyme electrode was described based on the immobilization of horseradish peroxidase (HRP) on dithiobis-N-succinimidyl propionate (DTSP) self-assembled monolayer (SAM) formed on gold-nanoparticles (Au-NPs) which were electrochemically deposited onto glassy carbon electrode (GCE) surface. The overall surface area and average size of Au-NPs could be controlled by varying deposition time and were examined by Field Emission-Scanning Electron Microscope (FE-SEM). The $O_2$ reduction capability of the surface demonstrated that Au-NPs were thermodynamically stable enough to stay on GCE surface. The immobilized HRP electrode based on Au-NPs/GCE presented faster, more stable and sensitive amperometric response in the reduction of hydrogen peroxide than a HRP immobilized on DTSP/gold plate electrode not containing Au-NPs. The effects of operating potential, mediator concentration, and pH of buffer electrolyte solution on the performance of the HRP biosensor were investigated. In the optimized experimental conditions, the HRP immobilized GCE incorporating smaller-sized Au-NPs showed higher electrocatalytic activity due to the high surface area to volume ratio of Au-NPs in the biosensor. The HRP electrode showed a linear response to $H_2O_2$ in the concentration range of 1.4 $\mu$M-3.1 mM. The apparent Michaelis-Menten constant ($K _M\; ^{app}$) determined for the immobilized HRP electrodes showed a trend to be decreased by decreasing size of Au-NPs electrodeposited onto GCE.

• Clean Technology
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• v.20 no.3
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• pp.277-282
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• 2014

In this study, PU-LMO was made by immobilization of LMO on urethane foam (PU) with using an EVA as a binder. PU-LMO was characterized by using X-Ray Diffractometer (XRD) and Scanning Electron Microscopy (SEM). The optimal ratio of EVA/LMO for preparation of PU-LMO was 0.26 gEVA/gLMO. The adsorption of lithium ions by PU-LMO was found to follow the pseudo-second-order kinetic model. The equilibrium data fitted well with Langmuir isotherm model and the maximum removal capacity of lithium ions was 17.09 mg/g. The PU-LMO was found to have a remarkably high selectivity of lithium ions and high adsorption capacity because the distribution coefficient ($K_d$) of lithium ion was higher than those of other metal ions.

• Journal of the Korean Chemical Society
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• v.53 no.2
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• pp.144-151
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• 2009

An optode for cadmium ion determination has been designed by immobilization of dithizone on triacetylcellose membrane. When the optode membrane is introduced into a real samples containing cadmium, there is a color change from green to red, making it possible to use the change in absorbance at 611 nm as the analytical signal. The sensor could be used in the range of 0.3-3 ${\mu}g\;ml^{-1}$ (2.67-26.67 ${\mu}M$) of $Cd^{2+}$ ions with a limit of detection of 0.025 ${\mu}g\;ml^{-1}$ (25 ng $ml^{-1}$). The response time of optode is within 15 min depending on the concentration of $Cd^{2+}$ ions. It can be easily and completely regenerated by dilute EDTA solution. The effect of different possible interfering species has been examined and was shown the optode has a good selectivity. The results obtained for the determination of cadmium ion in polluted soil and water samples using the proposed optode was found to be comparable with the well-established atomic absorption method.

• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.166-171
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• 2006

In this study, in using a piezoelectric material of $Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$ (PMN-PT), which has a high electromechanical coupling coefficient, we have tried to study about this material can be practically available as a new biosensor to detect protein by using surface acoustic wave (SAW). As the results, the filtering of the center frequency of the PMN-PT substrate is a superior result to that of the $LiTaO_3$ (LT) substrate, but the result was not completely satisfactory. Also this study attempts to develop a sensing method to detect mismatched DNA in order to diagnose cancer. We could directly immobilize the MutS to the NTA using the EDC solution. But, we immobilized MutS using nickel and it is judged that is more effective method to detect mismatched DNA.