Browsing by Author "Wei, Ling-Fang"

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A coumarin-based fluorescent probe for thiols and its application in cell imaging
(2016-09)
Liao, Yu-Cheng
;
Venkatesan, Parthiban
;
Wei, Ling-Fang
;
Wu, Shu-Pao
;
應用化學系
A new coumarin-based fluorescent probe CAA containing an acrylamide group has been designed and synthesized for the detection of biothiols. The probe CAA shows high selectivity and sensitivity for cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) over other amino acids. A fluorescence turn-on response is induced by a Michael-type reaction. It shows a highly sensitive fluorescence emission to Cys, Hcy, and GSH, with detection limits of 192 nM for Cys, 158 nM for Hcy, and 155 nM for GSH (S/N = 3). Furthermore, confocal fluorescence microscopy imaging using RAW264.7 macrophages demonstrates that CAA can be an effective fluorescent probe for thiols in living cells. (C) 2016 Elsevier B.V. All rights reserved.
A hypochlorous acid turn-on fluorescent probe based on HOCl-promoted oxime oxidation and its application in cell imaging
(2014-06-01)
Yu, Shiang-Yi
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Hsu, Chen-Yi
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Chen, Wei-Chieh
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Wei, Ling-Fang
;
Wu, Shu-Pao
A coumarin-based fluorometric probe, HS1, has been successfully developed for highly sensitive and selective detection of hypochlorous acid (HOCl). The probe is based on the specific HOCl-promoted oxidation of oxime. The reaction is accompanied by a 7-fold increase in the fluorescent quantum yield (from 0.03 to 0.21). The fluorescence intensity of the reaction between HOCl and HS1 shows a good linearity in the HOCl concentration range of 1-20 mu M and a low detection limit of 25 nM (S/N = 3). In addition, confocal fluorescence microscopy imaging using RAW264.7 macrophages demonstrates that the HS1 probe could be an efficient fluorescent probe for HOCl in living cells. (C) 2014 Elsevier B.V. All rights reserved.
A nano-molar fluorescent turn-on probe for copper(II) detection in living cells
(2019-09-15)
Wei, Ling-Fang
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Chen, Chong-Yan
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Lai, Chia-Kai
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Thirumalaivasan, Natesan
;
Wu, Shu-Pao
The development of fluorescent probes to detect trace metal ions in biological samples has been in great need. Herein, a fluorescence turn-on sensor (PHC) was designed for highly selective detection of Cu2+ ions. The probe PHC shows weak fluorescence due to imine isomerization. With Cu2+, a significant blue emission due to Cu2+-induced oxidation of imine to a carboxylate group is observed. The turn-on process is observed with a 63-fold increase of fluorescence quantum yield (from 0.004 to 0.252). The emission intensity has a good linear relation at Cu2+ concentrations of 0-40 mu M. The detection limit is estimated as 8 nM (S/N = 3). The maximum emission change induced by Cu2+ is found in the pH range of 6.5-8.0. The probe PHC can be applied in detecting Cu2+ in living cells monitored by confocal fluorescence microscopy imaging.
Fluorescent coumarin-based probe for cysteine and homocysteine with live cell application
(2017-08-05)
Wei, Ling-Fang
;
Thirumalaivasan, Natesan
;
Liao, Yu-Cheng
;
Wu, Shu-Pao
;
應用化學系
Cysteine (Cys) and homocysteine (Hcy) are two of important biological thiols and function as important roles in several biological processes. The development of Cys and Hcy probes will help to explore the functions of biothiols in biological systems. In this work, a new coumarin-based probe AC, containing an acryloyl moiety, was developed for Cys and Hcy detection in cells. Cys and Hcy undergo a nucleophilic addition and subsequent cyclization reaction to remove to the acryloyl group and yield a fluorescent product, 7-hydroxylcomuarin. The probe AC showed good selectivity for cysteine and homocysteine over glutathione and other amino acids and had low detection limits of 65 nM for Cys and 79 nM for Hcy, respectively. Additionally, confocal imaging experiments demonstrated that the probe AC can be applied to visualize Cys and Hcy in living cells. (C) 2017 Elsevier B.V. All rights reserved.