Phenazine‐Based Fluorescence “Turn‐Off” Sensor for Fluoride: Application on Real Samples and to Cell and Zebrafish Imaging

Abstract

In the present work, we report the design of a novel chemosensor 2-(1H-indole-3-yl)- 1H-imidazo[4,5-b]phenazine, (R) for fluoride ion detection via a naked eye observable colour change from light yellow to brown along with 10 fold ratiometric fluorescence quenching from green to no fluorescence in a matrix containing a large number of similar toxic anions in aqueous dimethylsulfoxide (30% H 2 O + DMSO) solution. The sensing mechanism was ascertained to be the fluoride triggered deprotonation of imidazole as well as indole moiety of R which is supported by 1:2 saturation level equivalence of R-F -. R was fully characterized through FT-IR, 1 H, 13 C NMR and HRMS. R is an effective receptor for Fwithin a wide range of pH that indicates its bio-compatibility. LoD and K a for Fwere found to be 1.8 × 10 -6 M (below 0.34 mg/Liter) and 2.7 × 10 4 M -1 respectively. The experimental observations were supported by the theoretical calculations using density functional theory. R also showed its potential practical applicability for fluoride detection in toothpaste solution. Furthermore, to prove its nontoxicity, probe R also applied to a cytotoxicity assay of HeLa cells followed by confocal fluorescence cells imaging and Zebrafish imaging experiments.[a] S. Naha, Prof. S. Velmathi

Tetraphenylethylene-Substituted Bis(thienyl)imidazole (DTITPE), An Efficient Molecular Sensor for the Detection and Quantification of Fluoride Ions

“…Using Equation ( 3) and the UV-vis. spectroscopic titration data, the detection limit of DTITPE was found tobe 1.37 × 10 −7 M. The limit of detection of DTITPE is one order of magnitude less than those of related imidazole-derived chemosensors, such as the phenazine (1.8 × 10 −6 M) [56] and anthraimidazoledione-based (0.5 × 10 −6 M) [57] fluoride sensors (See Table S4). Furthermore, using Equation (4) and the results from the UV-vis.…”

Highly Sensitive Optical Sensor for Selective Detection of Fluoride Level in Drinking Water: Methodology to Fabrication of Prototype Device

“…The obtained LOD values are well below the recommended limit (1.5 ppm) proposed by WHO as well as comparably low with respect to the recently reported spectroscopy based sensors. 12,[45][46][47] The low detection limit and linear response of the sensor for a wide range of fluoride concentrations make it a promising candidate in the field of fluoride sensing.…”

“…This in turn makes its detection a tedious prospect. 12 Till date, a great variety of methods have been employed for the precise determination of Fin water, such as ISE (Ion Selective Electrode), 13 ion chromatography, 14 HR-ICP-MS (High Resolution Inductively Coupled Plasma Mass Spectrometry), 15 AAS (Atomic Absorption Spectroscopy), 16 MAS (Molecular Absorption Spectroscopy) 17 etc. However, most of these conventional methods are costly, time consuming and require sophisticated instruments and expert hands to process.…”

“…Among the other toxic anions, fluoride is considered to be particularly detrimental due to its small size, high charge density, strong basic property and capability of making H-bonding. This in turn makes its detection a tedious prospect . Till date, a great variety of methods have been employed for the precise determination of F – in water, such as ISE (Ion Selective Electrode), IC (Ion Chromatography), ICP-MS (Inductively Coupled Plasma Mass Spectrometry), AAS (Atomic Absorption Spectroscopy), ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy), and so on.…”

Neutral Red-carbon nanodots for selective fluorescent DNA sensing

“…Phenazines present antimicrobial activity, anti-oomycete activity, genotoxicity, and cytotoxicity [20]. Based on their unique electrochemical and optical properties, they have also different important applications such as in the development of electrochemical sensors [21] and biosensors [22], optical assays [23], in particular those based on their fluorescence [24,25], and fabrication of dye-sensitized solar cells (DSSCs) [26][27][28]. All of these excellent properties can be acquired by a nanomaterial as CDs, if it is modified with a phenazine.…”