Journal of Fluorescence最新文献

DNA aptamer sequences were selected in silico with assistance from artificial intelligence (AI) using the new Xelari.com platform against three known immunogenic surface proteins of Treponema pallidum designated Tpp17, Tpp47 and Tp0751. The in silico aptamers were synthesized with 5' Alexa Fluor 647 labels and shown to bind live Treponema pallidum by fluorescence microscopy and spectrofluorometry. While AI-predicted K_d values differed somewhat from measured K_d values, it is clear that the aptamers bound the T. pallidum surface which is consistent with the molecular docking models for each aptamer with each cognate target protein all of which are thought to be largely accessible for binding (i.e., not predominately embedded in the outer membrane or cell wall). All three aptamers also demonstrated good specificity in cross-reactivity binding studies.

Herein, multifunctional fluorescent N-doped carbon dots (N-CDs) are synthesized from O-phenylenediamine and 4-aminobenzoic acid. Hydrothermal synthesis and nitrogen doping make the N-CDs possess good physical and chemical properties with bright emission at 567 nm (QY = 32%) and present obvious excitation dependence. Among common metal ions, only Cr(VI) strongly and linearly decrease the yellow fluorescence of N-CDs in wide concentration ranges of 20.0-180 µM and 180-350 µM. Thus, N-CDs are constructed as efficient fluorescence probe for Cr(VI) with detection limit of 1.94 µM. The mechanism of quenching is indicated as the inner filter effect (IFE). The proposed sensor has been successfully applied in two kinds of water samples. In addition, the CDs are tried to apply for cell imaging. Above experiments prove that N-CDs based sensors are efficient strategies for sensitive Cr(VI) detection and cell imaging.

Intracellular microviscosity is a key physicochemical parameter that influences molecular diffusion, signal transduction, and organelle function. However, fluorescence probes capable of selectively visualizing viscosity dynamics with high sensitivity and biological compatibility remain limited. Here, we report a dihydroxanthene-based viscosity-responsive fluorescent probe, ZKW, constructed with a D-π-A push-pull architecture and an o-bromophenyl molecular rotor. ZKW displays a pronounced viscosity-dependent fluorescence enhancement at 580 nm upon 550 nm excitation, originating from restricted intramolecular rotation and suppressed TICT processes. The probe exhibits good selectivity toward viscosity with negligible interference from polarity, pH, reactive species, metal ions, amino acids, or proteins, along with acceptable photostability and low cytotoxicity. Colocalization studies revealed preferential mitochondrial accumulation with partial lysosomal distribution, enabling simultaneous visualization of viscosity variations in these organelles. Using multiple cellular stress models-including LPS stimulation, oleic-acid treatment, nystatin exposure, and erastin-induced ferroptosis-ZKW effectively reported viscosity elevations at the subcellular level. These results establish ZKW as a robust and versatile tool for probing microviscosity heterogeneity in living cells and for facilitating studies of viscosity-associated physiological and pathological processes.

The breakthrough of high-power lasers urged the effective light quenching materials for safeguarding eyes,sensors and photo detectors. Encountered exploration of novel carbon dots to manipulate the ray of light at a modest price. Nonetheless, a carbon dot suffers from a large spectral range detection of a ray of light, so the research has been devoted to exploring the materials to cover different spectral ranges. This article reports a novel dual-photon emissive carbon dot with large spectral emission coverage with an effortless preparation strategy. The rapid fabrication procedure constituted with dualcolour emissive carbon dots(MCCD) in a single solvent with utilization of biomass source. We have identified the mono-solvent effect induced dual emissive carbon dots observed in fluorescence spectroscopy. The fluorescence carbon particle displays the nature of excitation-independent behaviour, with an average granule size of 16.93 nm, result obtained via Transmission electron microscopy. The carbon structure suffered from the lower carbonization temperature with rapid microwave treatment, causing a turbostratic carbon structure. The dual colour contains with NIR region bright red emission solution tested against Z-scan non-linear properties, it exposes the excited state absorption involved in two-photon absorption. It offers an approach for optical limiting behaviour, with threshold reaches up to 0.53 × 10^- 10 and 4.54 × 10¹² W/m² was observed for MCCD. These result in a gateway for eco-friendly carbon dots into an optical limiting appeal.