A 2-(2′-hydroxyphenyl)benzothiazole (HBT)–quinoline conjugate: a highly specific fluorescent probe for Hg²⁺ based on ESIPT and its application in bioimaging

Abstract

A benzothiazole derived chemosensor L has been designed based on the excited-state intramolecular proton transfer (ESIPT) mechanism to afford a fluorescence turn-on response specifically in the presence of Hg(2+) ions over a host of biologically relevant metal ions as well as toxic heavy metal ions. The chemosensor exhibits high sensitivity with the detection limit down to 0.11 μM. The metal binding is supported by (1)H NMR titrations, ESI-MS spectral analysis and substantiated by theoretical calculations using the density functional theory. The probe shows cell membrane permeability and efficiency for the detection of Hg(2+) in HeLa cells.

Cytotoxic 2‐(2′‐Hydroxyphenyl)benzothiazolylquinoline Analogues and their In Vitro Screening through Developmental Assays†

“…Likewise, 8‐hydroxyquinoline has been established as an antibacterial, antiseptic, and potential anticancer agent . Recently, 2‐(2′‐hydroxyphenyl)benzothiazole (HBT)–quinoline based probe showed cell membrane permeability and efficiency for detection of Hg 2+ in HeLa cells . In unremitting search of cancer theranostic drugs, our groups have established a set of novel cancer theranostic benzothiazolyl‐quinoline conjugates .…”

“…[12][13][14][15] Recently, 2-(2'hydroxyphenyl)benzothiazole (HBT)-quinoline based probe showed cell membrane permeability and efficiency for detection of Hg 2 + in HeLa cells. [16] In unremitting search of cancer theranostic drugs, our groups have established a set of novel cancer theranostic benzothiazolyl-quinoline conjugates. [17] These benzothiazolylquinoline scaffolds have proven potency and selectivity towards adenosine A 3 receptor; because expression of A 3 receptor is well known in cancer cell lines.…”

FRET‐based Fluorescent and Colorimetric Probe for Selective Detection of Hg(II) and Cu(II) with Dual‐mode

“…Zhang and co‐workers reported a fluorescent “turn‐off” sensor towards Cu 2+ with a detection limit of 4.9 nM in pure water at pH 3.5; this sensor was based on benzimidazo[2,1‐a]benz[de]isoquinoline‐7‐one. Bharadwaj and co‐workers developed a fluorescent “turn‐on” probe by covalently attaching 5‐(benzothiazol‐2‐yl)‐4‐hydroxyisophthalaldehyde onto 8‐aminoquinoline; this probe exhibited high sensitivity towards Hg 2+ with a detection limit down to 0.11 μM . Although many elaborate chemosensors with single functions can monitor Hg 2+ or Cu 2+ individually , designing dual‐function fluorescent probes for monitoring Hg 2+ and Cu 2+ is attractive.…”

Energy Donor Effect on the Sensing Performance for a Series of FRET-Based Two-Photon Fluorescent Hg2+ Probes

“…Studies have shown that exposure to mercury, even at very low concentrations, leads to various diseases in the digestive system, the nervous system, and especially the neurological system, which makes detection of mercury ions (Hg 2+ ) an attractive research area in the biological field [3,4]. Thus, much attention has been focused on developing new methods to monitor Hg 2+ in biological and environmental samples [5,6,7]. Among various kinds of methods, the fluorescent probe method shows important application value because of its high sensitivity, high selectivity, and low damage to samples [8].…”