Browsing by Author "Vijay, Natarajan"

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A triple action chemosensor for Cu2+ by chromogenic, Cr3+ by fluorogenic and CN- by relay recognition methods with bio-imaging of HeLa cells
(2017-09-01)
Vijay, Natarajan
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Balamurugan, Gopal
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Venkatesan, Parthiban
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Wu, Shu Pao
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Velmathi, Sivan
A triple action chemosensor (R1) bearing a rhodamine and thiophene moiety was synthesized by a simple condensation reaction. The sensing behaviour and selectivity of the synthesized chemosensor toward metal ions were studied by UV-Vis and fluorescence spectroscopy. The chemosensor recognized Cu2+ and Cr3+ ions with significant changes in UV-Vis absorbance and fluorescence intensity. The results showed that Cr3+ induced greater fluorescence enhancement whereas Cu2+ ions bound strongly with the receptor by showing a strong absorption band at 554 nm but with weak fluorescence. A visible colour change was observed by the addition of Cu2+ and that colour change is due to the opening of the spirolactam ring triggered by the addition of Cu2+ ions. Job's plot analysis indicated a 1 : 2 and 1 : 1 binding stoichiometry between the chemosensor and Cr3+/Cu2+. Subsequently, the R1 - Cu2+ complex chemosensor was employed to detect CN- in the presence of different anions, such as F-, Cl-, Br-, I-, AcO-, H2PO4-, HSO4-, NO3- and -OH. In addition, the live cell imaging of HeLa cells using R1 and Cr3+ was demonstrated successfully.
Coumarin-based Hg2+ fluorescent probe: Fluorescence turn-on detection for Hg2+ bioimaging in living cells and zebrafish
(2019-08-05)
Chen, Chong-Guang
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Vijay, Natarajan
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Thirumalaivasan, Natesan
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Velmathi, Sivan
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Wu, Shu-Pao
The need in developing fluorescent probes for trace metal ion detection in biological samples has been an important issue. Herein, a reaction-based fluorescent probe PIC containing a perimidine moiety was designed and synthesized for Hg2+ detection. The probe can selectively distinguish Hg2+ with 42-fold fluorescent enhancement from the other metal ions at physiological pH. This probe can detect Hg2+ with the detection limit of 1.08 mu M. The sensor PIC can be applied to real-time detection of Hg2+ in cells with blue emission. (C) 2019 Elsevier B.V. All rights reserved.
Turn on fluorescent chemosensor containing rhodamine B fluorophore for selective sensing and in vivo fluorescent imaging of Fe3+ ions in HeLa cell line and zebrafish
(2019-11-01)
Vijay, Natarajan
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Wu, Shu Pao
;
Velmathi, Sivan
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應用化學系
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Department of Applied Chemistry
Rhodamine dyes are utilized effectively as a chemosensor to monitor biologically important metal ions and effectively applied for fluorescent imaging studies in living systems. Herein, rhodamine-B armed fluorescent chemosensor (RhBNC) was designed and synthesized by condensation reaction between rhodamine B hydrazide and naphthyl chromone with ONO binding site in good yield. Upon sensing study towards metal ions, the probe showed selective turn-on fluorescent change for Fe3+ over other cations even in the presence of competing trivalent metal ions as well. The fluorescence switch is "on" when Fe3+ ions binds to RhBNC with orange fluorescence. The probe can detect lower concentration of Fe3+ ions with detection limit of 0.16 mu M. Due to its lower detection limit; it can be applied to monitor Fe3+ ion presence in a living system by fluorescent imaging technique. The probe was employed effectively to ascertain the presence of Fe3+ and to image Fe3+ ions in HeLa cell line and zebrafish.