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Zinc(II) Ion Sensing in Aqueous Micellar Solution Using Modified Bipyridine‐Based “Turn‐On” Fluorescent Probes and its Application in Bioimaging
Author(s) -
Pawar Shweta,
Akula Mahesh,
Labala Suman,
Venuganti Venkata Vamsi Krishna,
Bhattacharya Anupam,
Nag Amit
Publication year - 2016
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201600382
Subject(s) - chemistry , aqueous solution , micelle , fluorescence , quinoline , bromide , metal ions in aqueous solution , pyridine , sodium dodecyl sulfate , inorganic chemistry , metal , organic chemistry , physics , quantum mechanics
The bipyridine‐based constructs 4‐(pyridine‐2‐yl)‐3 H ‐pyrrolo[2,3‐ c ]quinoline (PPQ) and [6‐(3 H ‐pyrrolo[2,3‐ c ]quinolin‐4‐yl)pyridin‐2‐yl]methanol (PPQ‐OH) and their assemblies with surfactants are evaluated as turn‐on fluorescent sensors for Zn 2+ ions in aqueous solution. This study strives to overcome the problem of low water solubility of the hydrophobic PPQ and PPQ‐OH by using micelles. Whereas the ligands show selective sensing behavior for Zn 2+ over important biological cations including Na + , K + , Ca 2+ , Mg 2+ in anionic sodium dodecyl sulfate and non‐ionic Tween 80 micelles, no Zn 2+ sensing is observed in cationic cetyltrimethylammonium bromide micelles. Unlike in DMF, Cd 2+ interference is observed in aqueous conditions, which can be avoided either by performing the study at pH≥9 or by carrying out a time‐resolved fluorescence study. Analysis of the Job plot data, the fluorescence lifetimes, and experiments on varying micellar shape and pH, confirms that the coordination volume of the resulting octahedral metal complex and formation of a five‐membered chelate ring are critical factors for Cd 2+ interference. The described sensing systems are capable of detecting Zn 2+ ions at the micromolar level. Additionally, it is shown that PPQ and PPQ‐OH can be used to detect Zn 2+ in HeLa cells under physiological conditions in bioimaging studies.