Development of a Fluorescein-Based Probe with an “Off–On” Mechanism for Selective Detection of Copper (II) Ions and Its Application in Imaging of Living Cells

Abstract

Copper is a common metallic element that plays an extremely essential role in the physiological activities of living organisms. The slightest change in copper levels in the human body can trigger various diseases. Therefore, it is important to accurately and efficiently monitor copper ion levels in the human body. Recent studies have shown that fluorescent probes have obvious advantages in bioimaging and Cu2+ detection. Therefore, a novel Cu2+ probe (N2) was designed and synthesized from fluorescein, hydrazine hydrate and 5-p-nitrophenylfurfural that is sensitive to and can detect Cu2+ within 100 s. The response mechanism of the N2 probe to Cu2+ was studied by several methods such as Job’s plots and MS analysis, which showed that the Cu2+ and the N2 probe were coordinated in a complexation ratio of 1:1. In addition, compared with other cations investigated in this study, the N2 probe showed excellent selectivity and sensitivity to Cu2+, exhibiting distinct fluorescence absorption at 525 nm. Furthermore, in the equivalent range of 0.1–1.5, there is a good linear relationship between Cu2+ concentration and fluorescence intensity, and the detection limit is 0.10 μM. It is worth mentioning that the reversible reaction between the N2 probe and Cu2+, as well as the good biocompatibility shown by the probe in bioimaging, make it a promising candidate for Cu2+ biosensor applications.

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

“…Rhodamine-based probes 4.7 [10] Curcumin nanoparticles probe 1.4 [23] BINOL-based fluorescent sensor 1.5 [39] Coumarin thiazolyl-functionalized Schiff base 1.5 [40] Rhodamine 6G derivatives as probe 37.6 [41] 4-Phenylsemicarbazone 1,2-naphthoquinone-4-sulfonic acid probe 12 [42] Schiff base derivative 180 [43] Fluorescein-based probe 6.3 [44] Red beet pigment method as indicator 54 [45] Cellulose Schiff base 105 [46] Our proposed method 0.94 Our method T A B L E 2 Cu 2+ ion determination from water samples using the standard addition method (n = 3).…”

Shedding Light on Heavy Metal Contamination: Fluorescein-Based Chemosensor for Selective Detection of Hg2+ in Water

“…Fluorescein hydrazones can be obtained with high yields and without generating by-products, making them a valuable asset for optical chemosensors. Recently, numerous fluorescent chemosensors for ions such as Cu 2+ [ 35 , 36 , 37 ], Ni 2+ and Al 3+ [ 38 ], Zn 2+ [ 39 ], Cd 2+ [ 40 ], and Hg 2+ [ 27 , 28 , 29 ] were developed based on fluorescein. As for Hg 2+ chemosensors, 7-hydroxy-4-methylcoumarin-8-carbaldehyde [ 27 ], (pyridin-2-ylmethoxy)-naphthalene-1-carbaldehyde [ 28 ], and thiophene-2-aldehyde [ 29 ] were used as receptors.…”

Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging

“…Biocompatibility is the top priority when fluorescent materials are used in bio-fields; a great number of biocompatible fluorescent materials (BFMs) have been obtained, such as organic small-molecule dyes, fluorescent conjugated polymers, metal nanoclusters, rare earth ion-based nanoparticles (e.g., rare-earth-doped upconversion nanoparticles), quantum dots, carbon nanomaterials (e.g., carbon nanotubes and carbon nanodots) and various fluorescent proteins. This Special Issue, "Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging", includes twelve research articles covering biosensors based on ion sensors, the detection of pathological oxidative stress and disease detection [1][2][3][4][5][6][7][8][9][10][11][12], as well as four review articles focused on different types of fluorescent probes and biological applications [13][14][15][16].…”

“…This supramolecular system has excellent selectivity for Hg 2+ , and the detection limit is 7.17 × 10 −7 M [9]. Three works reported on biosensors for the detection of Cu 2+ , which are capable of monitoring the amount of Cu 2+ in cells [10][11][12][13].…”