Search

Copper, as the third most abundant transition metal ions of human, plays an essential role in the redox reaction, signal transduction, hematopoiesis, and other physiological processes. Abnormal content of copper ions in the body will cause some diseases such as anemia, coronary heart disease, Menkes’ syndrome. In this article, a new fluorescence probe L for Cu2+ was designed and synthetized by using 4-bromo-1,8 naphthalene anhydride and 2-thiophene formaldehyde as raw materials. Fluorescent probe L itself exhibited strong fluorescence, upon the addition of Cu2+ ions, the fluorescence was quenched. The fluorescent detection limit for Cu2+ ions was determined to be 1.8 μM based on a 3δ/S method. UV-vis absorption and fluorescence spectra indicated that probe L showed good selectivity and sensitivity for Cu2+, and this selectivity was not interfered by other metal ions and anions. Further cell fluorescence imaging experiments indicated that the probe L had potential to be used to examine copper ions in vivo. [ABSTRACT FROM AUTHOR]

Small-molecule thiols, such as cysteine (CYS) and glutathione (GSH), are essential for maintaining the cellular redox environment and play important roles in regulating various cellular physiological functions. A fluorescence probe (compound 1-Cu2+) for thiols based on coumarin carbohydrazide dinuclear copper complex was developed. Compound 1 was synthesized from the reaction of 7-(diethylamino)-2-oxo-2H-chromene-3-carbohydrazide with 4-tert-butyl-2,6- diformylphenol. Accordingly, the copper complex (compound 1-Cu2+) was prepared by mixing compound 1 with 2 equivalents copper ions. Compound 1 had strong fluorescence while compound 1-Cu2+ hardly possessed fluorescence owing to the quenching nature of paramagnetism Cu2+ to the fluorescence molecule excited state. However, the fluorescence intensity of compound 1-Cu2+ was increased dramatically after the addition of thiol-containing amino acids, but not the other non-sulfhydryl amino acids. UV-vis absorption and fluorescence spectra indicated that compound 1-Cu2+ had good selectivity and sensitivity for thiols such as glutathione in CH3CN:H2O (3:2, v/v) PBS solution. The fluorescence imaging experiments implied that compound 1-Cu2+ has potential application in thiol-containing amino acids detection in living cells. [ABSTRACT FROM AUTHOR]

Abstract: A system based on FRET mechanism, comprising a coumarin donor and a rhodamine acceptor, was developed for the selective and quantitative detection of metal ions. Fluorescent chemosensors RCs, linked by 1,2-diethylamine, exhibit significant fluorescence enhancement and excellent selectivity toward Cu2+. Fluorescent probes CRB and CR6G, linked by hydrazide, function as ratiometric receptors for Cu2+ chromogentically and fluorogentically in organic-aqueous media. Furthermore, the characteristic rhodamine-based fluorescence response of CRB (excitation at 550 nm) exhibits high selectivity for Hg(II). The construction of this kind of universal FRET system opens a broader prospect for future design of ratiometric fluorescent probes. [ABSTRACT FROM AUTHOR]

By the incorporation of coumarin fluorophores within the benzyldihydrazone moiety and by carefully adjusting the redox potential of the fluorophore and its excited state energy, one of the brightest Cu2+-binding sensors in aqueous media was achieved and could be used for the detection of Cu2+in living cells. [ABSTRACT FROM AUTHOR]

A water-soluble fingerprint probe, GK-Ac, was designed and synthesized by using an unsymmetric structure of fluorescent groups. In the present contribution, incorporating a "rotor" structure to impede the rotation of rotational site groups, which can effectively enhance aggregation-induced emission and provide additional sites for modification. The results indicate that the fingerprint probe GK-Ac had faint fluorescence characteristics in aqueous solution, and the level 2 structure of latent fingerprints can be clearly observed at 450 nm fluorescence when soaked in lipid or sprayed with the GK-Ac aqueous solution. Moreover, the probe was also successfully applied to detect the level 3 structure of latent fingerprints with flat surfaces. The results can provide reliable theoretical guidance for the development of fingerprint fluorescence developer. [Display omitted] • An AIE-based water-soluble probe was designed and synthesized by using an unsymmetric structure. • The level 3 features of LFPs can be revealed by soaking or spraying with the GK-Ac. • GK-Ac only binds to lipids on LFPs and does not bind to other substances. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel resorufin-based fluorescent probe for selective detection of NE was developed. • Probe displayed rapid response time (<10 min) and high selectivity towards NE. • Probe could detect endogenous NE and exocytosis process by fluorescent imaging in living cells and depression-like behavior mice. Norepinephrine (NE), as an important neurotransmitter, is closely associated with the pathogenesis of anxiety and depressive disorders. Effective monitoring of NE fluctuation aids in the diagnosis of depression and the therapeutic assessment of the antidepressant intervention. The construction of novel fluorescent probes with high specificity towards NE for imaging in depression models is still in demand urgently. In this work, a novel resorufin-based red-emitting fluorescent probe for real-time tracking NE was developed. NE can significantly increase the fluorescence of probe LNE by triggering deprotection of carbonothioate ligand via nucleophilic substitution. The probe LNE demonstrated significant NE selectivity and sensitivity over other analytes in vitro. In addition, probe LNE showed a fast response time (<10 min), and the change in fluorescence signal was positively linked with NE concentration, which could be utilized to track the dysregulation of NE in vivo. More importantly, this powerful probe was successfully employed for real-time visual and imaging of NE in living cells and depression-like behavior animals. [ABSTRACT FROM AUTHOR]

A fluorescence "turn-on" probe for Cu (Ⅱ) ions was prepared based on the condensation reaction of coumaraldehyde and 1-hydroxy-2-acetylnaphthalene. A strong fluorescent flavonoid intermediate was formed and verified by the NMR and ESI-MS experiments. The water-soluble and pH dependence experiments were performed to confirm the optimal solvent condition (CH 3 CN: HEPES = 1:1, v/v, pH = 7.2–7.4). The dynamic experiments indicated that the formation process of the intermediate catalyzed by Cu(Ⅱ) ions was probably pseudo-first-order reaction process. The probe showed good selectivity toward copper ions and almost no interference except Ag+ ions by the selectivity and competitive experiments. The HeLa cells were used in the cell fluorescence imaging tests and it was demonstrated that the probe could be used in the phycological condition and showed weak cytotoxicity by the MTT experiments. [Display omitted] • A Cu2+ ions biosensor was constructed by the condensation reaction of coumaraldehyde and 1-hydroxy-2-acetylnaphthalene. • The probe exhibited high selectivity for Cu2+ and could not be disturbed even if high concentration of GSH existed. • The mechanism probably involved the procedure of copper-mediated cyclization to generate the flavonoid intermediate. • The probe can be used to detect Cu2+ ions in physiological environment proven by the cell image experiments. [ABSTRACT FROM AUTHOR]

A specific Cu2+ sensor, 2-amino-3-(BODIPYmethyleneamino)maleonitrile (BDM), was established by a simple dehydration between BODIPY and diaminomaleonitrile. Cu2+ could be recognized by BDM over other competing metal ions in acetonitrile with distinct fluorescence emission signal response. Upon the addition of Cu2+ to BDM in acetonitrile, the maximum absorption at approximately 530 nm on the longer wavelength side was quenched, and the emission at 530 nm was ignited simultaneously. The fluorescence intensity enhancement could reach a maximum of 204 times the intensity of the BDM blank solution. The fluorescence "off-on" effect is established according to the Cu2+-induced fast intramolecular oxidative cyclization reaction, which could be deduced from the formation of an imidazole ring appended to the cyclization product (2-BODIPY-1 H -imidazole-4,5-dicarbonitrile, BMC). Single-crystal structure analysis of the sensor BDM and cyclization product BMC further demonstrated this oxidative cyclization. Finally, the Cu2+ recognition property of BDM was validated in SiHa cells and living zebrafish. Additionally, the blood-brain barrier of the zebrafish can be penetrated by the BDM dye and the neuron cells in the brain were stained. Unlabelled Image • Intramolecular oxidative cyclization reaction based sensor was established. • Single crystal structure analysis was also demonstrated. • Sensing property was validated in Siha cells and living vertebrate model, zebrafish. [ABSTRACT FROM AUTHOR]

A novel fluorescent probe 1 was synthesized for the detection of thiophenol on the basis of a unique thiophenol-mediated substitution-cyclization reaction. The probe 1 displayed 420-fold fluorescence intensity enhancement and highly selective and sensitive response for thiophenol over other competing sulfur species. This probe showed an excellent linear relationship in 10–140 μM and the low detection limit of 29 nM. The recognition mechanism of probe 1 toward PhSH was supported by the NMR spectrum and ESI-MS. Furthermore, the probe 1 was successfully applied for detection of thiophenol in living HepG2 cells. Image 1 • A novel fluorescent probe 1 for thiophenol was constructed on the basis of substitution-cyclization reaction. • Probe 1 features significant fluorescence enhancement up to 420-fold in response to thiophenol in aqueous solution. • This probe showed an excellent and wide linear relationship in 10–140 μM and with a low detection limit of 29 nM. • The probe could detect thiophenol in living cells. [ABSTRACT FROM AUTHOR]