• 세라미스트
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• 제22권3호
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• pp.281-300
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• 2019

Surface enhanced Raman scattering (SERS) was first discovered in 1974 by an unexpected Raman signal increase from Pyridine adsorbed on rough Ag electrode surfaces by the M. Fleishmann group. M. Moskovits group suggested that this phenomenon could be caused by surface plasmon resonance (SPR), which is a collective oscillation of free electrons at the surface of metal nanostructures by an external light source. After about 40 years, the SERS study has attracted great attention as a biomolecule analysis technology, and more than 2500 new papers and 500 review papers related to SERS topic have been published each year in recently. The advantages of biomaterials analysis using SERS are as follows; ① Molecular level analysis is possible based on unique fingerprint information of biomolecule, ② There is no photo-bleaching effect of the Raman reporters, allowing long-term monitoring of biomaterials compared to fluorescence microscopy, ③ SERS peak bandwidth is approximately 10 to 100 times narrower than fluorescence emission from organic phosphor or quantum dot, resulting in higher analysis accuracy, ④ Single excitation wavelength allows analysis of various biomaterials, ⑤ By utilizing near-infrared (NIR) SERS-activated nanostructures and NIR excitation lasers, auto-fluorescence noise in the visible wavelength range can be avoided from in vivo experiment and light damage in living cells can be minimized compared to visible lasers, ⑥ The weak Raman signal of the water molecule makes it easy to analyze biomaterials in aqueous solutions. For this reason, SERS is attracting attention as a next-generation non-invasive medical diagnostic device as well as substance analysis. In this review, the principles of SERS and various biomaterial analysis principles using SERS analysis will be introduced through recent research papers.

• 공업화학
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• 제28권2호
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• pp.177-185
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• 2017

본 연구에서는 스테아르산(SA), 올레산(OA), 리놀레산(LA) 등의 지방산이 지질 소포체 막과의 상호 작용에 미치는 영향에 관하여 살펴보았다. 이를 위하여 지방산 종류 및 농도 변화에 따른 리포좀 평균 입자 크기 및 제타 전위, 리포좀 막의 deformability, fluorescence anisotropy ratio 등을 측정하고 TEM 관찰을 통하여 지방산 첨가가 리포좀 막의 유동성 변화에 미치는 역할에 관하여 살펴보았다. 기본적으로 SA, OA, LA 등의 지방산 첨가는 동일한 경향을 나타내었다. 즉, 지방산을 첨가함에 따라 리포좀이 보다 치밀한 패킹을 갖게 되어서 리포좀의 크기는 감소하고 제타 전위 값은 증가하였으나, 지방산의 과도한 첨가는 리포좀에서 다형(polymorphic) 구조를 가지는 지질 입자 응집체로의 전이를 일으켰다. SA, OA 및 LA 지방산 시스템에서의 최소 리포좀 크기와 가장 치밀한 리포좀 패킹은 레시틴 대비 지방산의 몰 비율이 각각 0.70, 0.50, 0.25인 조건에서 관찰되었으며, 리포좀 막의 deformability와 fluorescence anisotropy ratio 측정에 의한 리포좀 막의 유동성 측정 결과는 TEM 및 입자 크기 측정 결과와 일치함을 알 수 있었다.

• 생체재료학회지
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• 제22권4호
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• pp.352-359
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• 2018

Background: Black phosphorus (BP) has emerged as a novel class of nanomaterials owing to its unique optical and electronic properties. BP, a two-dimensional (2D) nanomaterial, is a structure where phosphorenes are stacked together in layers by van der Waals interactions. However, although BP nanodots have many advantages, their biosafety and biological effect have not yet been elucidated as compared to the other nanomaterials. Therefore, it is particularly important to assess the cytotoxicity of BP nanodots for exploring their potentials as novel biomaterials. Methods: BP nanodots were prepared by exfoliation with a modified ultrasonication-assisted solution method. The physicochemical properties of BP nanodots were characterized by transmission electron microscopy, dynamic light scattering, Raman spectroscopy, and X-ray diffractometry. In addition, the cytotoxicity of BP nanodots against C2C12 myoblasts was evaluated. Moreover, their cell imaging potential was investigated. Results: Herein, we concentrated on evaluating the cytotoxicity of BP nanodots and investigating their cell imaging potential. It was revealed that the BP nanodots were cytocompatible at a low concentration, although the cell viability was decreased with increasing BP nanodot concentration. Furthermore, our results demonstrated that the cells took up the BP nanodots, and the BP nanodots exhibited green fluorescence. Conclusions: In conclusion, our findings suggest that the BP nanodots have suitable biocompatibility, and are promising candidates as fluorescence probes for biomedical imaging applications.

• Journal of Microbiology and Biotechnology
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• 제32권8호
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• pp.989-1002
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• 2022

Cephalopods, in particular octopus (Octopus vulgaris), have the ability to alter their appearance or body pattern by showing a wide range of camouflage by virtue of their chromatophores, which contain nanostructured granules of ommochrome pigments. Recently, the antioxidant and antimicrobial activities of ommochromes have become of great interest; therefore, in this study, the pH-dependent redox effect of the extraction solvent on the antioxidant potential and the structural characterization of the pigments were evaluated. Cell viability was determined by the microdilution method in broth by turbidity, MTT, resazurin, as well as fluorescence microscopy kit assays. A Live/Dead Double Staining Kit and an ROS Kit were used to elucidate the possible inhibitory mechanisms of ommochromes against bacterial and fungal strains. The results obtained revealed that the redox state alters the color changes of the ommochromes and is dependent on the pH in the extraction solvent. Natural phenoxazinone (ommochromes) is moderately toxic to the pathogens Staphylococcus aureus, Bacillus subtilis, Salmonella Typhimurium and Candida albicans, while the species Pseudomonas aeruginosa and Pseudomonas fluorescens, and the filamentous fungi Aspergillus parasiticus, Alternaria spp. and Fusarium verticillioides, were tolerant to these pigments. UV/visible spectral scanning and Fourier- transform infrared spectroscopy (FTIR) suggest the presence of reduced ommatin in methanol/ HCl extract with high intrinsic fluorescence.

• 대한소아치과학회지
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• 제46권3호
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• pp.265-273
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• 2019

이 연구는 레진침투법(resin infiltration, RI)을 적용하기 적합한 초기 유아기 우식증 병소를 동정하는데 있어 레이저 형광법(laser fluorescence, LF)의 활용 가능성을 평가하기 위해 수행되었다. 인접면 우식을 가진 20개의 자연 탈락 유구치를 이용, 중심와를 지나도록 협설로 절단하여 근원심 치면을 별개의 시편으로 간주하였다. ICDAS code 1과 2에 해당하는 시편 27개를 선별하였고 LF값을 측정하였다. 현미경 평가를 위해 RI 시행 시 이중 염색을 병행하였고, 절편을 제작하였다. 현미경 영상으로부터 병소깊이(최대 탈회깊이, $LD_{max}$), 최대 침투깊이($PD_{max}$), 평균 레진 침투율(Penetration rate, PR)을 측정하고, 상관분석을 시행하였다. LF값은 PR과 양의 상관관계를 보였으나 $LD_{max}$ 및 $PD_{max}$와는 유의성을 보이지 않았다. 얕은 법랑질 우식군을 제외하고, 깊은 법랑질 우식군과 상아질 우식군에서는 LF값과 PR 간에 유의한 상관관계가 확인되었다. 활동성 우식은 RI를 적용할 경우 침투율이 높고, LF 값이 보다 높게 측정될 수 있다. 진행 정도가 유사한 우식병소의 활성도를 평가하고자 할 경우, 레이저 형광법이 유용할 것으로 사료되었다.

• 대한방사성의약품학회지
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• 제8권2호
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• pp.53-61
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• 2022

This study aimed to increase the targeting ability against PSMA in cell therapy using metabolic glycoengineering and biorthogonal chemistry and to visualize cell trafficking using PET imaging. Cellular membranes of THP-1 cells were decorated with azide(-N₃) using Ac₄ManNAz by metabolic glycoengineering. Engineered THP-1 cells were conjugated with DBCO-bearing fluorophore (ADIBO-Cy5.5) for 1 h at different concentrations and analyzed by confocal fluorescence microscopy and flow cytometry. For PSAM ligand conjugation to THP-1 cells, Ac₄ManNAz treated THP-1 cells were incubated with DBCO-PSMA ligand (ADIBO-GUL) at a final concentration with 100 µM for 1 h. To evaluate the effect on cell recognition, PSMA ligand conjugated THP-1 cells(as effectors) were co-cultured with PSMA positive 22RV1 (as target cells) at 3 : 1 a effector-to-target cell (E/T) ratio. The interaction between THP-1 and 22RV1 was monitored by confocal fluorescence microscopy. For preparing the radiolabeled THP-1, the cells were treated at the activity of ~ 740 kBq of [⁸⁹Zr]Zr(oxinate)₄/5 × 10⁶ cells. Radiolabeled cells were analyzed for determination of cell-associated radioactivity by gamma counting and viability using MTS assay. In the cytotoxicity assay, THP-1 cells did not have any cytotoxicity even when the Ac₄ManNAz concentration was 100 µM. In confocal microscopy and flow cytometry, THP-1 cells were efficiently labeled ADIBO-Cy5.5 in a dose-dependent manner, and the dose of 100 µM was the optimal concentration for the following experiments. The clusters of PSMA ligand-conjugated THP-1 cells and 22RV1 cells were identified, indicating cell-cell recognition over the cell surface between two types of cells. Cell radiolabeling efficiency was 54.5 ± 17.8%. THP-1 labeled with 0.09 ± 0.03 Bq/cell showed no significant cytotoxicity compared to unlabeled THP-1 up to 7 days. We successfully demonstrated that Ac₄ManNAz treated cells were efficiently conjugated with ADIBO-GUL for preparing the PSMA-targeting cells, and [⁸⁹Zr]Zr(oxinate)₄ could be used to label cells without toxicity. It suggested that PSMA-ligand conjugated cell therapy could be improved cell targeting and be monitored by PET imaging.

• 한국세라믹학회지
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• 제49권3호
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• pp.221-225
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• 2012

It is possible to enhance the color of the natural diamond with a high pressure high temperature(HPHT) process. We employed a pyrophyllite tube cell and cubic press apparatus for HPHT treatment on the brown colored Type II (5.6 GPa/ $1700^{\circ}C$/ 52 min), and Type I aB(5.6 GPa/ $1650^{\circ}C$/ 30 min) diamond samples. We investigated the microstructure, Types, fluorescence, properties of the diamonds with an optical microscopy, FT-IR, photoluminescence(PL) spectroscopy, Diamond-View, and micro-Raman spectroscopy. Two tinted brown diamonds changed into colorless just after the HPHT process. Optical microscopy showed that no crack and significant inclusion evolution occurred during the HPHT process except the small graphite spot appeared in Type I aB sample. FTIR spectrum confirmed that no Type, amber center, and platelet defect change with the HPHT treatment. Diamond-View could not distinguish the HPHT treated diamonds from the naturals. PL spectroscopy showed that N3 and H3 color centers remained even after HPHT process. Consequently, we successfully changed the color of diamonds into colorless by 5.6 GPa HPHT process.

• Macromolecular Research
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• 제15권4호
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• pp.330-336
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• 2007

Luminescent CdSe/ZnS QDs, with emission in the red region of the spectrum, were synthesized and encapsulated in poly(ethylene glycol)-poly(D,L-lactide) diblock copolymer micelles, to prepare water-soluble, bio-compatible QD micelles. PEG-PLA diblock copolymers were synthesized by ring opening polymerization of D,L-lactide, in the presence of methoxy PEG as a macro initiator. QDs were encapsulated with PEG-PLA polymers using a solid dispersion method in chloroform. The resultant polymer micelles, with encapsulated QDs, were characterized using various analytical techniques, such as UV- Vis measurement, light scattering, fluorescence spectroscopy, transmission electron microscopy (TEM) and atomic forced microscopy (AFM). The polymer micelles, with encapsulated QDs, were spherical and showed diameters in the range of 20-150 nm. The encapsulated QDs were highly luminescent, and have high potential for applications in biomedical imaging and detection.

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2193-2198
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• 2011

We prepared polycatenar 1H-imidazole amphiphiles having a structure in which a 1H-imidazole head was connected through a benzene ring to a pheny group having two or three oligo(ethylene glycol) chains and studied their supramolecular assembly by fluorescence spectroscopy, transmission electron microscopy (TEM) and atomic force microscopy (AFM). When the aqueous solutions of the amphiphiles ($5{\times}10^{-5}M{\sim}10^{-3}M$) were deposited onto a carbon-coated copper grid and dried, twisted structures with diameters of ~200-300 nm were imaged by TEM and AFM. We presume that the structures comprised a chain of the amphiphile dimers formed via successive hydrogen bonding between the 1H of the imidazole group and 3N of the neighboring one. In a solution of pH 4, entangled fibers with diameters of several nanometers were observed by TEM. In a pH 10 solution, film-like aggregates formed exclusively. The 1H-imidazole amphiphiles hydrolyzed tetraethoxysilane to induce gelation to form fibrous and spherical silica structures at neutral pH in aqueous solutions. No silica was formed when imidazole was used instead of the amphiphiles, suggesting that the selfassembled aggregates of the amphiphiles were responsible for the gelation.

• Journal of the Optical Society of Korea
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• 제14권4호
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• pp.431-437
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• 2010

A stack of gradient-index (GRIN) rod lenses cannot be used for coherent anti-Stokes Raman scattering (CARS) microendoscopy for insertion to internal organs through a surgical keyhole with minimal invasiveness. That's because GRIN lens has large amount of inherent chromatic aberrations in spite of absolutely requiring a common focus for pump and Stokes beam with each frequency of ${\omega}_p$ and ${\omega}_S$. For this endoscopic purpose, we need to develop a long slender probe-type objective, namely probe-type microscope objective (PMO). In this paper, we introduce the structure, the working principle, and the design techniques of PMO which is composed of a probe-type lens module (PLM) and an adaptor lens module (ALM). PLM is first designed for a long slender type and ALM is successively designed by using several design parameters from PLM for eliminating optical discords between scanning unit and PLM. A combined module is optimized again to eliminate some coupling disparities between PLM and ALM for the best PMO. As a result, we can obtain a long slender PMO with perfectly diffraction-limited performance for pump beam of 817 nm and Stokes beam of 1064 nm.