A novel ratiometric fluorescent probe, namely 5-[(3-dicyanoylidene -5.5-dimethyl) cyclohexenyl-1-ethenyl] salicylaldehyde-3'-hydroxybenzohydrazone (DCSH) is presented for the selective sensing of Zn ion in acetonitrile/water (2/3, pH 7.4) solution. Introducing Zn ions notably caused the peak emission of DCSH to shift from 560 nm to 646 nm, accompanied with a significant enhancement of its intensity. A vivid change in fluorescence color from yellow to red facilitated the immediate identification of Zn ions by visual observation. DCSH exhibits substantial Stokes shifts (110 and 196 nm), rapid detection capability (within 10 s) and high sensitivity to Zn ions, achieving a limit of detection of 31.2 nM. The response mechanism is supposed to involve the block of C = N bond isomerization and excited state intramolecular proton transfer (ESIPT) along with the enhancement of fluorescence through chelation (CHEF) effect. DCSH was effectively utilized for ratiometric fluorescence imaging to monitor exogenous Zn concentrations in HeLa cells. Significantly, DCSH is capable of monitoring elevated levels of Zn ion during apoptosis induced by L-Buthionine sulfoximine (BSO).
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http://dx.doi.org/10.1016/j.saa.2024.124645 | DOI Listing |
Mikrochim Acta
January 2025
School of Pharmaceutical Science, Hengyang Medical School, University of South China, Hengyang, 421001, China.
A ratiometric fluorescent nanoprobe (CDs-Rho), synthesized through the simple covalent amide linkage between carbon dots (CDs) and pH-sensitive rhodamine dye (Rho), was designed for the precise sensing and imaging of extremely alkaline environments. The sensing mechanism involves the opposite pH-dependent fluorescence changes in CDs and Rho, respectively, coupled with pH-regulated FRET efficiency from CDs to Rho. The nanoprobe features a wide pH response window from pH 7.
View Article and Find Full Text PDFJ Agric Food Chem
January 2025
College of Quality and Technical Supervision, Hebei University, Baoding 071002, China.
The extensive use of tetracyclines in livestock poses health risks due to their residues in animal-derived food; therefore, developing simple detection methods to replace complex traditional approaches is of paramount importance. Here, we developed a dual-ligand zinc-based metal-organic framework material, Zn-BTC-BDC-NH (denoted as ZTD), for the detection of tetracyclines. The intrinsic blue fluorescence of ZTD was quenched upon the introduction of tetracyclines due to electron transfer from -NH of ZTD to -CO- and -OH groups of tetracycline molecules; meanwhile, the new green fluorescence emission was generated through π-π stacking between aromatic rings and the formation of complexes between Zn and C-O/C═O groups.
View Article and Find Full Text PDFBiosensors (Basel)
January 2025
Laboratory of Biochemistry, Molecular Biology and Bioluminescent Systems Technology, Department of Physics, Chemistry and Mathematics, Federal University of Sao Carlos (UFSCAR), Rodovia João Leme dos Santos, km 110, Sorocaba 18052-780, SP, Brazil.
Firefly luciferases have been extensively used for bioanalytical applications, including their use as bioluminescent reporters, biosensors, and for bioimaging biological and pathological processes. Due to their intrinsic pH- sensitivity, in recent years we have demonstrated that firefly luciferases can also be harnessed as color- tuning sensors of intracellular pH. However, it is known that mammalian cells require temperatures higher than 36 °C, which red-shift the bioluminescence spectra of most firefly luciferases, decreasing their activities and the resolution of ratiometric pH analysis.
View Article and Find Full Text PDFDev Dyn
January 2025
Department of Medicine, Michigan State University College of Human Medicine, East Lansing, Michigan, USA.
Disruption of extracellular pH and proton-sensing can profoundly impact cellular and protein functions, leading to developmental defects. To visualize changes in extracellular pH in the developing embryo, we generated a zebrafish transgenic line that ubiquitously expresses the ratiometric pH-sensitive fluorescent protein pHluorin2, tethered to the extracellular face of the plasma membrane using a glycosylphosphatidylinositol (GPI) anchor. Monitoring of pHluorin2 with ratiometric fluorescence revealed dynamic and discrete domains of extracellular acidification over the first 72 h of embryonic development.
View Article and Find Full Text PDFAnal Methods
January 2025
Jiangxi University of Chinese Medicine, Nan Chang, Jiangxi 330004, China.
This study reports a novel ratiometric fluorescence sensor based on a tetraphenylethylene-bipyridine covalent organic framework (TPE-Bpy-COF) for the sensitive detection of Cu, leveraging the unique coordination properties of the bipyridine moieties. The interaction between Cu and the nitrogen atoms in the bipyridine units induces fluorescence quenching at 500 nm through an efficient host-guest electron transfer mechanism, where excited-state electrons from the COF framework are transferred to the vacant orbitals of Cu. Upon excitation at 410 nm, the sensor exhibits a primary emission peak at 500 nm, which is quenched in the presence of Cu, while an overtone peak at 820 nm remains stable, serving as an internal reference for ratiometric measurements and significantly enhancing the accuracy and reliability of the sensor.
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