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Highly selective colorimetric detection of Zn(II) ions using label-free silver nanoparticles
Lee, Sujin,Nam, Yun-Sik,Lee, Ho-Jin,Lee, Yeonhee,Lee, Kang-Bong Elsevier 2016 Sensors and actuators. B Chemical Vol.237 No.-
<P><B>Abstract</B></P> <P>A simple and facile colorimetric method for the detection of zinc ions (Zn<SUP>2+</SUP>) using label-free silver nanoparticles (AgNPs) has been developed. Zn<SUP>2+</SUP> ions induced the aggregation of label-free AgNPs in solution, resulting in a color change from yellow to forest green, which was accompanied by the appearance of a new surface plasmon absorption band at 635nm. The sensitivity of label-free AgNPs towards other metal ions was negligible, with the exception of Fe<SUP>3+</SUP>, which caused a modest interference. The binding site and sensing mechanism for Zn<SUP>2+</SUP> ions in label-free AgNPs were characterized by Fourier Transform infrared spectroscopy, ultraviolet-visible spectroscopy, and transmission electron microscopy. The aggregation of AgNPs in the presence of Zn<SUP>2+</SUP> ions was inhibited by polyvinyl alcohol, which formed a shell on the surface of AgNPs. Furthermore, Zn<SUP>2+</SUP> ions coordinated with BH<SUB>4</SUB> <SUP>−</SUP> on AgNPs through a triangular sixdentate binding structure, thus inducing aggregation of AgNPs in solution.</P> <P>The sensor conditions were optimized with 6.0μM of sodium dodecylbenzenesulfonate (NaDDBS) and 0.23mM AgNPs at pH 6. The absorption ratios (A<SUB>635</SUB>/A<SUB>390</SUB>) of the label-free AgNPs solution exhibited a linear correlation with Zn<SUP>2+</SUP> ion concentration within the range of 0.0−7.6×10<SUP>−6</SUP> molL<SUP>−1</SUP>, with a limit of detection of 0.36×10<SUP>−6</SUP> molL<SUP>−1</SUP>. This cost-effective sensing system allows rapid and facile determination of Zn<SUP>2+</SUP> ions in various types of biological, mineral supplement, and environmental samples.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A facile silver nanoparticle sensor for the visual detection of Zn<SUP>2+</SUP> ion. </LI> <LI> A colorimetric Zn<SUP>2+</SUP> ion sensor using label-free silver nanoparticle. </LI> <LI> This sensor exhibits excellent selectivity for Zn<SUP>2+</SUP> ion over other metal ions. </LI> <LI> This simple sensor can detect ∼0.36×10<SUP>−6</SUP> molL<SUP>−1</SUP> concentration of Zn<SUP>2+</SUP> ion within 15min. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Resistant Mechanism of Escherichia coli to HK 3140 - a New Fluoroquinolone
Yeonhee Lee,Sonduk Lee,Myung Hwan Park,Taeseuk Lee,Jaedu Ha,Jae Yang Kong Wan Joo Kim 생화학분자생물학회 1993 BMB Reports Vol.26 No.4
In our study, the resistant mechanism of Escherichia coli to a new fluoroquinolone-HK3140 (Kim et al., 1991) was characterized. In the presence of carbonylcyanide m-chlorophenyl hydrozone (CCCP), HK3140 uptake was increased and in vivo DNA synthesis was inhibited. This result suggested that both susceptible and resistant strains have efflux systems which are proton gradient dependent. The resistant strain had another efflux system which was ATPase dependent. DNA synthesis of the permeabilized resistant cells was less inhibited by HK3140 than that of the permeabilized susceptible cells. Results suggested that the resistant mechanism against HK3140 came from an ATPase dependent efflux system and changes in DNA gyrase and porin proteins (Lee et al., 1992).
Lee, Kyenam,Lee, Yeonhee 서울여자대학교 자연과학연구소 2002 자연과학연구논문집 Vol.14 No.-
Lactic acid producing bacteria (LAB) reduced the number of Escherichia coli in fresh juice in less than 6 h without changing pH and taste. Results in this study suggested LAB as a preventive measure for fresh juice without fermentation.
Investigation of Polyesters by Time-of-Flight Secondary Ion Mass Spectrometry
Lee, Yeonhee,Han, Seunghee,Hercules, David M. 한국분석과학회 1995 분석과학 Vol.8 No.4
The structural characterization for series of polyesters has been done by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Polymer fragments and intact oligomers composed of large numbers of repeat units have been investigated. Transesterification of polyesters in trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CFA) was monitored and reaction products were identified using TOF-SIMS. The shapes and intensities of clusters in transesterification spectra show good agreement with the theoretical isotope pattern. TOF-SIMS spectra were used to obtain information about the progress of the transesterification reaction.
Evaluation of Twenty Fluoroqunolones with MRSA
Lee, Soondeuk,Lee, Yeonhee 서울여자대학교 자연과학연구소 1997 자연과학연구논문집 Vol.9 No.-
임상에서 분리한 533개의 methicillin resistant Staphylococcus aureus (MRSA)를 20개의 불화 퀴놀론에 대한 감수성 정도에 따라 5개의 군으로 나누었다. 각 군에서 5개의 균주를 무작위로 선발하여 각 항생제의 투과도, 배출효과 및 DNA gyrase에 대한 억제 효과에 관하여 연구하였다. 대부분의 MRSA가 불화퀴놀론에 대하여 내성을 나타냈으며, 특히 기존의 불화퀴놀론인 ciprofloxacin, norfloxacin, ofloxacin, sparfloxacln에 대하여는 40% 이상의 MRSA가 내성을 나타냈다. MIC 및 disk test의 결과에 의하면 기존의 불화 퀴놀론보다는 KR-series가 MRSA에 대하여 더 좋은 억제효과를 나타냈다. 그 중 KR10984와 KR11048이 가장 강력한 억제효과를 나타냈으며, 대부분의 MRSA가 이들에 대해 감수성을 보였다. 세포내로의 투과도가 좋거나 배출이 잘 안되는 불화퀴놀론보다는 불화 퀴놀론의 작용부위인 DNA gyrase에 대한 억제도가 좋은 화합물이 낮은 MIC 값을 나타냈다. C-7기에 1-amino-5-azaspiro-[2,4]heptene-5-yl기를 갖는 불화 퀴놀론들이 DNA gyrase에 대하여 높은 억제효과를 나타내 이런 경우에 해당되었다.
HOW TO DEVELOPE NEW PRO BIOTIC WITH ANTI Helicobacter pylori FUNCTION
Yeonhee Lee 한국식품영양과학회 2001 한국식품영양과학회 학술대회발표집 Vol.50 No.-
Lactic acid producing bacteria were isolated from baby feces and characterized to be used as a probiotic with anti Helicobacter pylori functions. The selected bacteria had inhibition activity on the adherance and growth of H. pylori. These bacteria had additional beneficial characteristics for the probiotic such as antibacterial activity, antitumor activity, immunostimulation activity, resistance to antibiotic and bile salt, ability to bind to the intestinal cells, and safe for the human use.