• Journal of Biomedical Engineering Research
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• v.30 no.2
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• pp.122-128
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• 2009

Cancer serum biomarkers have advanced our ability to more accurately predict tumor classification, prognostic/metastatic potential, and response potential to novel chemotherapies. Serum amyloid A (SAA) and Vascular endothelial growth factor (VEGF) have potential utility as a serum biomarker for lung cancer. Quantum dots, nanometer-sized crystals, have a high quantum yield, sensitivity, and pronounced photostability. The properties of quantum dots can be efficiently applied to the detection of serum biomarkers in immunoassays as fluorescent probe. We used quantum dots as fluorescent probes in immunoassays and attempted to detect serum amyloid A and vascular endothelial growth factor as serum biomarkers of lung cancer. This fluorescence immunoassay based on the properties of quantum dots is applicable to the detection of serum biomarkers for lung cancer. The fluorescence immunoassay with quantum dots should allow the efficient and specific detection of serum amyloid A (SAA) for the possible diagnosis of lung cancer.

• Journal of Soil and Groundwater Environment
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• v.21 no.3
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• pp.1-5
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• 2016

Rhodamine B Hydrazide as a novel fluorescent and colorimetric probe exhibiting remarkably selective fluorescence enhancement toward Hg²⁺ ion over other 16 metal ions is herein introduced. The probe reacts with Hg²⁺ ion followed by its spirolactam ring-opening to give a remarkable enhancement of absorption maximum at 550 nm as well as an enhanced fluorescence intensity at 580 nm in aqueous media. Upon titration with Hg²⁺ ion in various concentration of 10~200 uM, we found that the probe shows a marked color change from colorless to pink, enabling naked-eye detection toward mercury ion. In addition, in the presence of Hg²⁺ ion, the probe gave rise to change from non-florescence to strong orange fluorescence (Off-On) with a good linearity of R²=0.97. This preliminary results demonstrate that the fluorescent chemosensor we herein introduced can open a new strategy for marked selective and sensitive detection of mercury ions in contaminated soil containing various metal ions.

• Analytical Science and Technology
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• v.16 no.6
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• pp.499-503
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• 2003

A high performance liquid chromatography gradient elution method with fluorescence detection for the determination of biotin in pure form and pharmaceutical preparations has been developed. BrMDMC gives intense fluorescence and the fluorescence was monitored with excitation at 360 nm and emission at 410 nm. The calibration curve for biotin shows good linearity over the range of 5 ~ 400 ng with correlation coefficient of 0.999. The detection limit of biotin was 2 ng and the result of recovery was 98.75% with relative standard deviation of 1.1%.

• Journal of Dairy Science and Biotechnology
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• v.33 no.4
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• pp.271-275
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• 2015

Colloidal semiconductor CdSe-ZnS core-shell nanocrystal quantum dot (Qdot) are luminescent inorganic fluorophores that show potential to overcome some of the functional limitations encountered with organic dyes in fluorescence labeling applications. Salmonella Enteritidis has emerged as a major cause of human salmonellosis worldwide since the 1980s. A rapid, specific, and sensitive method for the detection of Salmonella Enteritidis was developed using Qdot as a fluorescence marker coupled with immunomagnetic separation. Magnetic beads coated with anti-Salmonella Enteritidis antibodies were employed to selectively capture the target bacteria, and biotin-conjugated anti-Salmonella antibodies were added to form sandwich immune complexes. After magnetic separation, the immune complexes were labeled with Qdot via biotin-streptavidin conjugation, and fluorescence measurement was carried out using a fluorescence measurement system. The detection limit of the Qdot method was a Salmonella Enteritidis concentration of $10^3$ colony-forming units (CFU)/mL, whereas the conventional fluorescein isothiocyanate-based method required over $10^5CFU/mL$. The total detection time was within 2 h. In addition to the potential for general nanotechnology development, these results suggest a new rapid detection method of various pathogenic bacteria from a complex food matrix.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2400-2402
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• 2014

Cu (II) detection is of great importance owing to its significant function in various biological processes. In this report, we developed a novel coumarin-based chemosensor bearing the salicylaldimine unit (2) for $Cu^{2+}$ selective detection. The results from fluorescence spectra demonstrated that the sensor could selectively recognize $Cu^{2+}$ over other metal cations and the detection limit is as low as $0.2{\mu}M$. Moreover, the confocal fluorescence imaging in HepG2 cells illustrated its potential for biological applications.

• Journal of Microbiology and Biotechnology
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• v.18 no.10
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• pp.1689-1694
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• 2008

The ability to detect Salmonella spp. is essential in the prevention of foodborne illness. This study examined a Salmonella spp. detection method involving the application of immunomagnetic separation and immunoliposomes (IMS/IL) encapsulating sulforhodamine B (SRB), a fluorescent dye. A quantitative assay was conducted by measuring the fluorescence intensity of SRB that was produced from an immunomagnetic bead-Salmonella spp.-immunoliposome complex. The results indicated detection limits of $2.7{\times}10^{5}$ and $5.2{\times}10^{3}$ CFU/ml for Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) and Salmonella enterka subsp. enterka serovar Typhimurium (S. Typhimurium), respectivley. The signal/noise ratio was improved by using 4% skim milk as a wash solution rather than 2% BSA. In addition, higher fluorescence intensity was obtained by increasing the liposome size. Compared with the conventional plating method, which takes 3-4 days for the isolation and identification of Salmonella spp., the total assay time of to h only including 6 h of culture enrichment was necessary for the Salmonella detection by IMS/IL. These results indicate that the IMS/ IL has great potential as an alternative rapid method for Salmonella detection.

• Current Applied Physics
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• v.18 no.11
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• pp.1255-1260
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• 2018

In this work, a green and simple one-pot route was developed for the synthesis of highly fluorescent aminofunctionalized graphene quantum dots (a-GQDs) via hydrothermal process without any further modification or surface passivation. We synthesized the a-GQDs using glucose as the carbon source and ammonium as a functionalizing agent without the use of a strong acid, oxidant, or other toxic chemical reagent. The as-obtained aGQDs have a uniform size of 3-4 nm, high contents of amino groups, and show a bright green emission with high quantum yield of 32.8%. Furthermore, the a-GQDs show effective fluorescence quenching for $Cu^{2+}$ ions which can serve as effective fluorescent probe for the detection of $Cu^{2+}$. The fluorescent probe using the obtained aGQDs exhibits high sensitivity and selectivity toward $Cu^{2+}$ with the limit of detection as low as 5.6 nM. The mechanism of the $Cu^{2+}$ induced fluorescence quenching of a-GQDs can be attributed to the electron transfer by the formation of metal complex between $Cu^{2+}$ and the amino groups on the surface of a-GQDs. These results suggest great potential for the simple and green synthesis of functionalized GQDs and a practical sensing platform for $Cu^{2+}$ detection in environmental and biological applications.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.109-118
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• 1999

The aim of this study was to evaluate the optical density of laser fluorescence for detection of incipient caries. Prepared and polished bovine enamel specimens were demineralized in a STPP solution for varying periods of time between 3 hrs. and 60 hrs. with an area of sound enamel retained on each specimen. The randomized specimens were analyzed for optical density of enamel demineralization using laser fluorescence. The specimens were sectioned and examined lesion depth by polarizing light microscope. Results were analyzed statistically with SAS program. The results from this study can be summarized as follows: 1. Optical density measured by laser fluorescence and lesion depth measured by polarizing light microscope was increased as demineralization time was increased(p<0.001). 2. Between optical density measured by laser fluorescence and lesion depth measured by polarizing light microscope was correlated highly(${\gamma}{\geq}0.74956$, p<0.001). 3. Regressive equation was obtained in this study as follows. Y=[X-0.260851]/0.000271(R-square:0.5618, p<0.001) (X:DENSITY, Y:DEPTH) In summary, optical density measured by laser fluorescence would be within the range of possibility to quantitatively presume demineralization amount of incipient caries lesion

• Archives of Pharmacal Research
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• v.28 no.10
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• pp.1111-1113
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• 2005

5-Aminolevulinic acid and its derivatives, which are known to affect the early diagnosis and treatment of cancer, have been synthesized. Simple methods for the synthesis of 5-aminole-vulinic acid (ALA), a precursor of porphyrins, have been developed in our laboratory for use in studies on the biosynthesis of porphyrins.

• Journal of Integrative Natural Science
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• v.3 no.4
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• pp.215-218
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• 2010

cis,cis-1,2,3,4-Tetraphenylbutadiene has been synthesized and its optical properties are investigated by using UV-Vis absorption and fluorescence spectroscopy. Thin films of tetraphenylbutadiene prepared from thin layer chromatography(TLC) displays strong luminescence and used for the detection of vapor of organic halide. Tetraphenylbutadiene shows dramatic quenching photoluminescence under exposure of chloroform vapor.