A reversible and highly selective two-photon fluorescent “on–off–on” probe for biological Cu²⁺ detection

Abstract

A two-photon active probe for physiological copper (Cu2+) detection is expected to play an important role in monitoring biological metabolism. Herein, a novel Schiff base derivative (E)-2,2'-((4-((4-(diethylamino)-2-hydroxybenzylidene)amino)phenyl)azanediyl)bis(ethan-1-ol) (L) with remarkable two-photon activity was developed and synthetically investigated. L presents high selectivity and sensitivity for Cu2+ sensing in ethanol/HEPES buffer (v/v, 1 : 1), which is accompanied by the fluorescence switching "off" and subsequently "on" with the addition of EDTA. The mechanism for the detection of Cu2+ is further analyzed using 1H NMR titration, mass spectra and theoretical calculations. Furthermore, since the probe L possesses good photophysical properties, excellent biocompatibility and low cytotoxicity, it is successfully applied to track Cu2+ in the cellular endoplasmic reticulum by two-photon fluorescence imaging, showing its potential value for practical applications in biological systems.

A colorimetric and ratiometric fluorescent sensor for sequentially detecting Cu2+ and arginine based on a coumarin–rhodamine B derivative and its application for bioimaging

“…In the experiments of amino acid detection, the solutions containing 1-Cu 2+ complex were obtained by adding Cu 2+ (2.0 eq.) into a solution of the sensor 1 Instrumentation NMR spectra were obtained by a Bruker AV400 ( 1 H NMR 400 MHz, 13 C NMR 100 MHz) instrument using CD 2 Cl 2 and DMSOd 6 as solvent and tetramethylsilane (TMS) as the internal standard. Mass spectrometry analysis was performed on an Agilent 1100 ion trap MSD spectrometer.…”

“…Mp 427-428 K; 1 Fig. S13 †); 13 44.40, 43.87, 41.47, 11.81, 11.68 (Fig. S14 †); ESI-MS (m/z): 826.42 [1 + H + ] + (Fig.…”

“…[9][10][11] So far, some uorescent sensors for the sensitive determination of Cu 2+ have been developed. [12][13][14] However, most of them are based on "turn-off" changes in uorescence intensity because Cu 2+ is usually used as a uorescent quencher via an energy or electron-transfer mechanism. [15][16][17][18] Therefore, the sensitive "turn-on" uorescent sensors to monitor and visualize Cu 2+ are highly demanded.…”

A quinoline–benzothiazole-based chemosensor coupled with a smartphone for the rapid detection of In3+ ions

“…8-Hydroxyquinoline (8-HQ) and its substituted derivatives have attracted considerable interest due to their remarkable coordinating abilities and have found their way into various applications. These reagents have been applied for analytical [18][19][20][21] and separation purposes as well as for the formation of luminescent coordination compounds. [22][23][24] The 8-HQ unit has also proved to be a valuable building block for the construction of different articial receptors, 25,26 self-assembled systems and other supramolecular architectures.…”

A chemosensor with a paddle structure based on a BODIPY chromophore for sequential recognition of Cu2+ and HSO3−

“…Copper is an essential trace element for organisms and plays an important role in various biological processes such as catalysis of enzymes, gene expression and protein synthesis. [1][2][3][4][5] Under normal conditions, the allowable limit of Cu 2+ is 15.7-23.6 mM in blood and 20-30 mM in drinking water, respectively. 6,7 A moderate concentration of Cu 2+ is helpful to maintain the normal function of the body, but an excess concentration of Cu 2+ may cause many neurological complications such as Wilson's disease and Alzheimer's disease.…”