A novel OFF-ON-OFF fluorescence probe based on coumarin for Al3+ and F− detection and bioimaging in living cells (2023)

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy

Volume 211,

15 March 2019

, Pages 299-305

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https://doi.org/10.1016/j.saa.2018.12.022Get rights and content


A novel fluorescence probe L2 based on coumarin has been designed and synthesized. The probe L2 can be used for relay recognition of metal ions Al3+ and anion F in the aqueous HEPES buffer (0.05 M, pH = 7.4), and build a OFF-ON-OFF detection system. The probe showed high selectivity and sensitivity to target ions in the process of relay recognition, and the corresponding detection limit could be as low as 0.014 μM (Al3+) and 0.03 μM (F). Besides, the geometry optimizations of probe L2 and [L2 + Al3+] complex were carried out using the Gaussian 16 program based on DFT, and the identification mechanism of the probe was also discussed by the mass spectrometry and theoretical calculations. Moreover, the probe has also been successfully applied to detection of target ions in living cells.

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A novel OFF-ON-OFF fluorescence probe based on coumarin for Al3+ and F− detection and bioimaging in living cells (3)
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It is well known that the aluminum is the most abundant metal element in nature and its reserves account for about 8% of the earth's crust [1,2]. At the same time, the aluminum has the advantages of small density, good thermal conductivity and good ductility. So it has also been widely used in various fields, such as industrial production, aerospace materials, medical equipment, food additives, drinking-water purification, and so on [[3], [4], [5], [6]]. But the Al3+ is not a necessary trace element, and the intake of Al3+ ions will remain in various organs of the body. First, Al3+ ions are very easily deposited in brain tissue, which may cause brain damage and serious memory loss. The existence of excessive Al3+ ions can also lead to a series of biochemical reactions, which will affect the normal metabolism of human cells. Meanwhile, Al3+ ions can directly damage the activity of osteoblasts, thus inhibiting bone matrix synthesis [[7], [8], [9]]. Therefore, the harm of Al3+ ions to human body is not to be underestimated.

Similarly, the fluorine also plays a very important role in many chemical and biomedical industry [10,11]. The fluoride is the common ingredient of the anesthetic, hypnotic, psychotropic drugs and military nerve gases. Meanwhile, fluorinated compounds also can be used to prevent dental caries, and they are usually added to some oral hygiene products. Fluorine is widely distributed in natural water, and fluorine is also found in all tissues of human body, mainly accumulated in teeth and bone tendons. A proper amount of F ions is essential for the human body, but excessive intake of fluoride is also harmful to people's health. The fluorosis is a typical symptom caused by chronic fluorosis [12,13]. High concentration of fluoride can also cause serious pulmonary edema, pulmonary hemorrhage, arrhythmia, nausea and strong irritation in the eyes and upper respiratory tract. Even more, it will also endanger human life [14,15]. From the point of view of environment and human health, it is very necessary to develop effective detection methods for fluoride.

In recent years, fluorescence sensing detection technology has attracted wide attention. Compared with the traditional detection technology, the fluorescence detection technology can show better detection results and have better application value and potential. Therefore, the construction of fluorescent probes with specific recognition performance has become one of the most popular research projects at home and abroad [16,17]. For the fluorescent probes that had been reported, most of them were some metal ions fluorescent probes and anion fluorescent probes. And many of them have some probes can be used for specific detection and identification of Al3+ or F [[18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29]]. However, many probes are usually limited by lengthy synthetic routes or high detection limits, which cannot be applied to practical detection applications. Most importantly, most of those probes are single response, although the selectivity of probes to the target ions is good, but the utilization ratio is not high compared to the relay response or the multi response probe. Therefore, the design and synthesis of fluorescent probes with high selectivity, high sensitivity and low cost, which can break through a single response type, is still a challenging subject.

In this paper, coumarin was used as the fluorescent group, a novel fluorescent probe (L2) with simple structure and good fluorescence response performance was designed and synthesized. The probe L2 can be used for relay recognition of metal ions Al3+ and anion F, and build an OFF-ON-OFF detection system. The optical properties and detection properties of probe L2 were systematically studied through a series of UV–Vis spectra and fluorescence emission spectra. At the same time, the influences of other common anion and cation on the detection effect of probe L2 were also discussed. Finally, probe L2 was used for fluorescence imaging analysis of target ions in living cells.

Section snippets

Materials and Instruments

Unless otherwise noted, all the solvents and inorganic salts were purchased from Sinopharm Chemical Reagent Ltd., The 4-hydroxy-4-biphenylcarbonitrile, hexamethylenetetramine, Rhodamine B and hydrazine hydrate (85%) were purchased from Aladdin Chemical Reagent Ltd., and used without further purification. The 1H NMR spectra were recorded on an AVANCEII 400 MHz spectrometer (Bruker BioSpin) and 13C NMR spectra were recorded on 101 MHz spectrometers. Mass Spectrometry (MS) were measured by a

The Selectivity of Probe L2 to Al3+

The fluorescence respond of the probe L2 were investigated by measuring the fluorescence emission spectra in the presence of different metal ions including Pb2+, Mg2+, Cd2+, Co2+, Cu2+, Ni2+, Fe2+, Al3+, Mn2+, Hg2+, K+, Li+, Na+, Fe3+, Cr3+ and Zn2+. As shown in Fig. 1, the single probe L2 presented an extremely weak fluorescence emission at 461 nm (Φ = 0.02). When 10 equiv. Al3+ was added, the emission peak of the probe system at 461 nm increased significantly (Φ = 0.41). But under the same


A novel schiff base fluorescent probe (L2) based on coumarin fluorescence was designed and synthesized. The probe L2 can be successfully applied to relay recognition detection of Al3+ and F. First, the probe L2 has high selectivity and anti-interference ability for Al3+. The main phenomenon is that the system changed from no fluorescence to strong blue fluorescence emission. And the titration experiments also showed that the probe L2 has excellent sensitivity to Al3+ and the minimum detection


This work was supported by the National Natural Science Foundation of China (No. 31470434, 21576124, 21507047 and 21676124), the China Postdoctoral Science Foundation funded project (No. 2017M610308), and the project supported by the Science Foundation of Jiangsu Entry-exit Inspection Quarantine Bureau (No.2017KJ47). Meanwhile, thanks to Spartan HPC computing service of University of Melbourne.

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