• Journal of the Korean Chemical Society
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• v.53 no.1
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• pp.84-89
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• 2009

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.472-472
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• 2005

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.741-741
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• 2005

• Journal of Microbiology and Biotechnology
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• v.1 no.2
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• pp.130-135
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• 1991

The effects of media composition on citric acid fermentation using surface immobilized Saccharomycopsis lipolytica were studied. The use of the standard medium for these organisms resulted in rapid decrease of citric acid production and a transformation of immobilized cell morphologies from a yeast-type to a mycelium-type. When the standard medium was enriched with vitamins, trace minerals, a growth factor and ammonium to form a Vigorous Stationary Phase (VSP) fermentation type medium, relatively stable citric acid production (10 mg/lㆍh) was obtained. Using the VSP type medium, the surface immobilized cells also retained their yeast-type form.

• Journal of Sensor Science and Technology
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• v.20 no.4
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• pp.226-229
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• 2011

Label-free detection of biomolecular interactions was performed using BioFET(Biologically sensitive Field-Effect Transistor) and SPR(Surface Plasmon Resonance). Qualitative information on the immobilization of an anti-IgG and antibody-antigen interaction was gained using the SPR analysis system. The BioFET was used to explore the pI value of the protein and to monitor biomolecular interactions which caused an effective charge change at the gate surface resulting in a drain current change. The results show that the BioFET can be a useful monitoring tool for biomolecular interactions and is complimentary to the SPR system.

• Bulletin of the Korean Chemical Society
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• v.8 no.3
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• pp.133-137
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• 1987

Polysiloxane SE-54 liquid phase was immobilized on the support surface as coated in thin film via in-situ cross-linking. The cross-linking between liquid molecules was initiated by dicumylperoxide. Among the supports investigated, only Chromosorb W provided the cross-linkable surface. The optimal in-situ cross-linking was achieved when Chromosorb W was coated with 5% (w/w) SE-54 and cross-linked with 1% (w/w) dicumylperoxide. The cross-linked support was useful for the trace analysis as well as for the trace enrichment.

• 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.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.88-92
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• 2005

Aptamer is the single-stranded oligonucleotide which binds to various target molecules such as proteins, peptides, lipids and small organic molecules with high affinity and specificity. DNA aptamers specific for the $17{\beta}-estradiol$ were selected by SELEX (Systematic Evolution of Ligands by EXponential enrichment) process from a random DNA library. These DNA aptamers have a high affinity to $17{\beta}-estradiol$ as an endocrine disrupting chemical. Nanowell and $200{\mu}m$ gold electrode were used as substrate for DNA aptamer immobilization and electrochemical analysis. Especially, nanowell gold electrode was fabricated by e-beam lithography. The size of single nanowell is 130nm and 40,000 nanowells were deposited on one gold electrode. The immobilization method was based on the interaction between the biotinylated aptamer and streptavidin deposited on gold electrode previously. Immobilization procedure was optimized by surface plasma resonance (SPR) and electrochemical analysis. After the immobilization of DNA aptamer on streptavidin modified gold electrode, $17{\beta}-estradiol$ solution was treated on aptamer immobilized gold electrode. The current of gold electrode was decreased by the binding of $17{\beta}-estradiol$ to DNA aptamer immobilized on gold electrode. However, in negative control experiments of 1-aminoanthraquinone and 2-methoxynaphthalene, the current was rarely decreased. And more sensitive data was obtained from nanowell gold electrode comparing with $200{\mu}m$ gold electrode.

• The Journal of the Acoustical Society of Korea
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• v.24 no.3
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• pp.160-165
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• 2005

We have developed SH (shear horizontal) surface acoustic wave (SAW) sensors for detection of the immobilization and hybridization of DNA (deoxyribonucleic acid) on the gold coated delay line of transverse SAW devices. The experiments of DNA immobilization and hybridization were performed with 15-mer oligonucleotides (probe and complementary target DNA). The sensor consists of twin SAW delay line oscillators operating at 100 MHz fabricated on $36^{\circ}$ rotated Y-cut $LiTaO_3$ piezoelectric single crystals. The relative change in the frequency of the two oscillators was monitored to detect the hybridization between target DNA and immobilized probe DNA in pH 7.4 PBS (phosphate buffered saline) solution. The measurement results showed a good response of the sensor to the mass loading effects of the DNA immobilization and hybridization with the sensitivity up to $1.55{\cal}ng/{\cal}ml/Hz$.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2408-2412
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• 2013

We demonstrate herein the synthesis and modification of magnetic nanoparticles and its use in the immobilization of the lipase. Magnetic $Fe_3O_4$ nanoparticles (MNPs) were prepared by simple co-precipitation method in aqueous medium and then subsequently modified with tetraethyl orthosilicate (TEOS) and 3-aminopropyl triethylenesilane (APTES). Silanization magnetic nanoparticles (SMNP) and amino magnetic nanomicrosphere (AMNP) were synthesized successfully. The morphology, structure, magnetic property and chemical composition of the synthetic MNP and its derivatives were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) analysis, X-ray diffraction, superconducting quantum interference device (SQUID) and thermogravimetric analyses (TGA). All of these three nanoparticles exhibited good crystallization performance, apparent superparamagnetism, and the saturation magnetization of MNP, SMNP, AMNP were 47.9 emu/g, 33.0 emu/g and 19.5 emu/g, respectively. The amino content was 5.66%. The AMNP was used to immobilize lipase, and the maximum adsorption capacity of the protein was 26.3 mg/g. The maximum maintained activity (88 percent) was achieved while the amount of immobilized lipase was 23.7 mg $g^{-1}$. Immobilization of enzyme on the magnetic nanoparticles can facilitate the isolation of reaction products from reaction mixture and thus lowers the cost of enzyme application.