• Macromolecular Research
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• v.17 no.5
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• pp.307-312
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• 2009

Core-shell hydrogel nanocomposite was fabricated by encapsulating a silica-gold nanoshell (SGNS) with poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAM-co-AAc) copolymer. The oleylamine-functionalized SONS was used as a nanotemplate for the shell-layer growth of hydrogel copolymer. APS (ammonium persulfate) was used as a polymerization initiator to produce a hydrogel-encapsulated SGNS (H-SGNS). The amounts of NIPAM (N-isopropylacrylamide) monomers were optimized to reproduce the hydrogel-encapsulated SGNS. The shell-layer thickness was increased with the increase of polymerization time and no further increase in the shell-layer thickness was clearly observed over 16 h. H-SGNS exhibited the systematic changes of particle size corresponding to the variation of pH and temperature, which was originated from hydrogen-bonding interaction between PNIPAM amide groups and water, as well as electrostatic forces attributed by the ionization of carboxylic groups in acrylic acid.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.474-477
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• 2005

Surface Plasmon Resonance(SPR) sensor system can be applicable for detecting of many biospecific interactions. In this study, the feasibility of the experimental $SPREETA^{TM}$ evaluation kit to analyze human IgG, Pseudomonas aeruginosa, was investigated. The sensor prepared for detecting of anti-human IgG has response on $0.1{\mu}{\ell}$ of the anti-human IgG solution. SPREETA was able to detect P. aeruginosa solution in the range above $10^8\;CFU/mL$ with the chitosan/ alginate multilayers.

• Vacuum Magazine
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• v.4 no.3
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• pp.12-15
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• 2017

Surface enhanced Raman scattering (SERS) is considered as one of promising medical and diagnostic technologies. The SERS effect is caused by the localized surface plasmon resonance (LSPR) from metal nanoparticles with narrow hot spots. The mechanism of LSPR, development of nanostructure fabrication, and corresponding researches are discussed. The flexible, label-free, low-cost, and highly-sensitive Au/ZnONRs/G is introduced. The Au/ZnONRs/G detects and distinguishes cataract, age-related macular degeneration, and diabetic macular edema from aqueous humor. Comprehension of SERS provides further improvement in bio sensing technology including early diagnosis and prolonged life expectancy.realize highly stretchable electrodes.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.132-134
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• 2005

The CC chemokine, monocyte chemoattractant protein-1 (MCP-1), plays a crucial role in the initiation of atherosclerosis and has direct effects that promote angiogenesis. To develop a specific inhibitor for MCP-1-induced angiogenesis, we performed in vitro selection employing phage display random peptide libraries. Most of the selected peptides were found to be homologous to the second extracellular loops of CCR2 and CCR3. We synthesized the peptide encoding the homologous sequences of the receptors and tested its effect on the MCP-1 induced angiogenesis. Surface Plasmon Resonance measurements demonstrated specific binding of the peptide to MCP-1 but not to the other homologous protein, MCP-3. Flow cytometry revealed that the peptide inhibited the MCP-1 binding to THP-1 monocytes. Moreover, CAM and rat aortic ring assays showed that the peptide inhibited MCP-1 induced angiogenesis. Our observations indicate that the MCP-1-binding peptide exerts its anti-angiogenic effect by interfering with the interaction between MCP-1 and its receptor.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.02a
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• pp.200-208
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• 2003

미생물수를 측정하는 가장 정확하고 보편적인 방법은 배양법이다. 그러나 배양법은 많은 시간과 노력이 소요되기 때문에 현장에서 실시간에 준하는 측정법으로 사용하기에는 원천적으로 한계를 가지고 있다. 이러한 한계를 극복하기 위해서는 실시간(real-time) 또는 준실시간(near real-time)으로 미생물을 검출할 수 있는 기술이 요구된다. 표면플라즈몬공명(surface plasmon resonance: SPR)은 생물분자 또는 미생물을 실시간 또는 준실시간으로 검출할 수 있는 센서로서 특이성(specificity)과 정확도(accuracy) 측면에서 일찍이 큰 관심을 받아왔다. 1902년, Wood(1902)는 반사 회절격자를 사용하여 연속광원의 스펙트럼을 관찰한 결과, 회절광 스펙트럼에서 어두운 좁은 밴드를 발견하였으며, Fano(1941)는 이 현상이 surface plasma waves와 관련이 있음을 이론적으로 밝혔다. (중략)

• Journal of Sensor Science and Technology
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• v.27 no.5
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• pp.275-279
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• 2018

In this study, we introduce a sensing platform based on a plasmonic metasurface absorber (MA) with a vertical nanogap for the ultrasensitive detection of monolayer molecules. The vertical nanogap of the MA, where the extremely high near-field is uniformly distributed and exposed to the external environment, is formed by an under-cut structure between a metallic cross nanoantenna and the mirror layer. The accessible sensing area and the enhanced near-field of the MA further enhance the sensitivity of surface-enhanced infrared absorption for the target molecule of 1-octadecanethiol. To provide strong coupling between the molecular vibrations and plasmonic resonance, the design parameters of the MA with a vertical nanogap are numerically designed.

• Applied Science and Convergence Technology
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• v.24 no.1
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• pp.1-8
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• 2015

Protein immobilization on a gold surface plays an important role in the usefulness of biosensors that utilize gold-coated surfaces such as surface plasmon resonance (SPR), quartz crystal microbalance (QCM), etc. For developing high performance biosensors, it is necessarily required that immobilized proteins must remain biologically active. Loss of protein activity and maintenance of its stability on transducer surfaces is directly associated with the choice of immobilization methods, affecting protein-protein interactions. During the past decade, a variety of strategies have been extensively developed for the effective immobilization of proteins in terms of the orientation, density, and stability of immobilized proteins on analytical devices operating on different principles. In this review, recent advances and novel strategies in protein immobilization technologies developed for biosensors are briefly discussed, thereby providing an useful information for the selection of appropriate immobilization approach.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.1031-1035
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• 2007

Prostate specific $antigen-{\alpha}_1-antichymotrypsin$ was detected by a double-enhancement strategy involving the exploitation of both colloidal gold nanoparticles (AuNPs) and precipitation of an insoluble product formed by HRP-biocatalyzed oxidation. The AuNPs were synthesized and conjugated with horse-radish peroxidase-PSA polyclonal antibody by physisorption. Using the protein-colloid for SPR-based detection of the PSPJACT complex showed their enhancement as being consistent with other previous studies with regard to AuNPs enhancement, while the enzyme precipitation using DAB substrate was applied for the first time and greatly amplified the signal. The limit of detection was found at as low as 0.027 ng/ml of the PSA/ACT complex (or 300 fM), which is much higher than that of previous reports. This study indicates another way to enhance SPR measurement, and it is generally applicable to other SPR-based immunoassays.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.755-756
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• 2005

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.197.1-197.1
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• 2014

VO2 has intensively investigated for several decades due to its interesting physical properties, including metal-insulator transition (MIT), thermochromic and thermoelectric properties, near the room temperature. And also gas and photo sensing properties of VO2 nanowires have attracted increasing research interest due to the high sensitivity and multi-sensing capability. We studied the light-induced resistance change of VO2 nanowires. In particular, we have investigated plasmonic enhancement of the photo-sensing properties of the VO2 nanowires. To select proper wavelength, we performed finite-difference time-domain simulations of electric field distribution in the VO2 nanowires attached with Ag nanoparticles. Localized surface plasmon resonance (LSPR) is expected at wavelength of 560 nm. The photo-sensitivity was carefully examined as a function of the sample temperature. In the presentation, we will discuss physical origins of the photo-induced resistance change in VO2.