Browsing by Author "Wu, Chi-Ming"

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CHARACTERISTICS OF ELECTROMAGNETIC INDUCTION BY MOVING FERROFLUIDS
(2012-07-01)
Chen, Ching-Yao
;
Wang, Sheng-Yan
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Wu, Chi-Ming
;
Lin, Chung-Hao
;
Huang, Kuo-An
We have demonstrated the capabilities to catch the signals of induced electromotive force (EMF). The characteristics of EMF signals are analyzed systematically. Influences of volumes, sizes and travelling velocities of ferrofluids on the magnitudes and wave spans of the signals are presented. In addition, simulations of the induction fields are carried out to provide the physical insights of the induced EMF signals. The signals can be potentially applied as diagnostic characteristics in the measurements of travelling velocities or sizes of moving ferrofluid drops or slugs.
Nitric Oxide Turn-on Fluorescent Probe Based on Deamination of Aromatic Primary Monoamines
(2012-05-07)
Shiue, Tsun-Wei
;
Chen, Yen-Hao
;
Wu, Chi-Ming
;
Singh, Gyan
;
Chen, Hsing-Yin
The stable, water-soluble, and nonfluorescent FA-OMe can sense nitric oxide (NO) and form the intensely fluorescent product dA-FA-OMe via reductive deamination of the aromatic primary amine. The reaction is accompanied by a notable increase of the fluorescent quantum yield from 1.5 to 88.8%. The deamination mechanism of FA-OMe with NO was proposed in this study. The turn-on fluorescence signals were performed by suppression of photoinduced electron transfer (PeT), which was demonstrated by density functional theory (DFT) calculations of the components forming FA-OMe and dA-FA-OMe. Furthermore, FA-OMe showed water solubility and good stability at physiological pHs. Moreover, the selectivity study indicated that FA-OMe had high specificity for NO over other reactive oxygen/nitrogen species. In an endogenously generated NO detection study, increasing the incubation time of FA-OMe with lipopolysaccharide (LPS) pretreated Raw 264.7 murine macrophages could cause an enhanced fluorescence intensity image. In addition, a diffusion/localization cell imaging study showed that FA-OMe could be trapped in Raw 264.7 cells. These cell imaging results demonstrated that FA-OMe could be used as a turn-on fluorescent sensor for the detection of endogenously generated NO.
Sensitivity evaluation of rhodamine B hydrazide towards nitric oxide and its application for macrophage cells imaging
(2011-12-05)
Wu, Chi-Ming
;
Chen, Yen-Hao
;
Dayananda, Kasala
;
Shiue, Tsun-Wei
;
Hung, Chen-Hsiung
A colorless and non-fluorescent rhodamine derivative, rhodamine B hydrazide (RH), is applied to detect nitric oxide and form fluorescent rhodamine B (RB). The reaction mechanism of RH with NO is proposed in this study. The probe shows good stability over a broad pH range (pH > 4). Furthermore, fluorescence intensity of RH displays an excellent linearity to the NO concentration and the detection limit is as low as 20 nM. A 1000-fold fluorescence turn-on from a dark background was observed. Moreover, the selectivity study indicated that the fluorescence intensity increasing in the presence of NO was significantly higher than those of other reactive oxygen/nitrogen species. In exogenously generated NO detection study, clear intracellular red fluorescence was observed in the presence of S-nitroso-N-acetyl-D,L-penicillamine (SNAP, a kind of NO releasing agent). In endogenously generated NO detection study, increasing incubation time of RH with lipopolysaccharied (LPS) pre-treated cells could obtain a highly fluorescent cell image. These cell imaging results demonstrated that RH can efficiently penetrate into Raw 264.7 cells and be used for detection of exogenously and endogenously generated nitric oxide. (C) 2011 Elsevier B.V. All rights reserved.