Application of 2,4,5‐tris(2‐pyridyl)imidazole as ‘turn‐off’ fluorescence sensor for Cu(II) and Hg(II) ions andin vitrocell imaging

Abstract

The 2,4,5-tris(2-pyridyl)imidazole (L) molecule has been evaluated as a probe for dual sensing of Hg 2+ and Cu 2+ ions in EtOH/HEPES buffer medium (5 mM, pH = 7.34, 1:1, v/v). Probe L shows a good sensitive and selective turn-off response in the presence of both Hg 2+ and Cu 2+ ions, which is comprehensible under long UV light. The probe can detect Cu 2+ ion in the pH range 3-11 and Hg 2+ ion in pH 6-8. The limit of detection for Cu 2+ (0.77 μM) is well under the allowable limit prescribed by the United States Environmental Protection Agency. Two metal (Cu 2+ /Hg 2+ ) ions are needed per L for complete fluorescence quenching. The probe shows marked reversibility on treatment with Na 2 EDTA, making the protocol more economical for practical purposes. Paper strip coated with the L solution of EtOH can detect the presence of Cu 2+ and Hg 2+ ions in the sample using visible quenching of the fluorescence intensity. Density functional theory-time-dependent density functional theory (DFT-TDDFT) calculations support experimental observations, and d-orbitals of Cu 2+ /Hg 2+ provide a nonradiative decay pathway. Cell imaging study using HDF and MDA-MB-231 cells also supported the viability of L in detecting Cu 2+ and Hg 2+ ions in living cells.

Comprehensive Insights into Medicinal Research on Imidazole-Based Supramolecular Complexes

“…The limit of detection (LOD) values toward Hg (II) and Cu (II) ions were 0.77 and 1.58 μM, respectively. Cell imaging studies using HDF and MDA-MB-231 cells also supported the viability of probe V10 in detecting Hg (II) and Cu (II) ions in living cells [ 487 ].…”

SDS‐capped 1‐pyrenecarboxaldehyde nanoprobe for selective detection of Cu2+ ion from water samples: Spectroscopic approach

“…However, high concentrations of copper can result in serious illness due to damage to the liver and kidney [11] and may cause conditions such as Alzheimer’s disease [12], Wilson’s disease [13], Parkinson's disease [14], prions disease [15] and diabetes [16]. Other health threats, such as Indian childhood cirrhosis and idiopathic copper toxicosis, have been reported due to the overloading of copper in children [17].…”

Imidazoles as Serotonin Receptor Modulators for Treatment of Depression: Structural Insights and Structure–Activity Relationship Studies

“…(e) Fluorescent probe-based peptide receptors detected intracellular Cu (I) ions in the Golgi apparatus (even in living A549 cells) [ 55 ]. (f) Tripyridyl imidazole molecule as a dual sensing probe of Hg (II) (pH 6–8) and Cu (II) (pH 3–11) ions detecting at 0.77 and 1.58 μM, respectively [ 56 ]. (g) Ruthenium (II) complexes containing imidazole as 1 O 2 -responsive fluorescent probes as an “on–off”-type fluorescent pH sensor (pK a1 = 1.12 ± 0.15, pK a2 = 6.90 ± 0.24, pK a1 * = 1.09, and pK a2 * = 6.92) [ 57 ].…”