Journal of Fluorescence最新文献

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.

Extensive surgical resection improves survival in cancer patients. Fluorescence-guided imaging techniques have significantly enhanced the precision of cancer resections. Triple-negative breast cancer (TNBC) lacks expression of the estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2), and no other targetable molecules have been identified. In this study, we verified that the L-type amino acid transporter 1 (LAT1, also known as SLC7A5) is overexpressed in triple-negative breast cancer (TNBC) cells and we constructed a novel near-infrared fluorescent dye Cys-PEG₅-IR target to SLC7A5. We then report the SLC7A5 receptor specificity of Cys-PEG₅-IR as a contrast agent for TNBC imaging in vitro and in vivo. The conjugation elevated cell fluorescence on SLC7A5-overexpressing TNBC cells and produced minimal cell fluorescence when treated with SLC7A5 knockdown. Tumor uptake of Cys-PEG₅-IR was significantly higher than the unlabeled IR in the subcutaneous MDA-MB-231 TNBC xenograft. This work highlights the prospect of using methionine (Met) transport pathway as an alternative strategy for targeting cancer cells, especially TNBC cells.

The present work deals with the preparation and characterization of novel g-C₃N₄/Fe₂WO₆ (GCNFW) nanocomposite for the effective detection and removal of Fe(III). where thermal polymerization (g-C₃N₄), ball milling - solid state reaction (Fe₂WO₆) and ultrasonication (GCNFW nanocomposite) methods were adopted for the preparation. The structural and morphological studies of GCNFW nanocomposite ensure the presence of single-phase orthorhombic Fe₂WO₆ decorated g-C₃N₄ and the same was free from impurities. The selectivity of GCNFW was tested by considering 15 metal ions namely Hg(II), Ni(II), Cd(II), Co(II), Sn(IV), Al(III), Cr(III), Pb(II), Zn(II), In(III), Fe(III), Cu(II), As(III), Sr(II) and Ba(II). Interestingly the prepared GCNFW nanocomposite could behave as fluorescent sensor and electrochemical sensor. As a fluorescent sensor, GCNFW has remarkable "Turn-off" fluorescence selectivity towards Fe(III) with LOD of 26.6 nM. The Differential Pulse Voltammetry (DPV) studies confirmed the electrochemical sensing behaviour of GCNFW towards Fe(III) with LOD of 1.23 µM. The prepared GCNFW has achieved 303.30 mg/g adsorption capacity and 87.48% removal efficiency within 15 min. A prototype water purifier made of GCNFW with Polyurethane foam (GCNFW-PU) could have the maximum adsorption capacity of 0.098 mg/g and removal efficiency of 99.36% towards Fe(III) in the real time drinking water samples collected from 7 different localities at Madurai District, Tamil Nadu. Hence the prepared GCNFW nanocomposite may serve as a promising fluorescent as well as electrochemical sensor material for the effective detection and removal of Fe(III) in the realm of heavy metals polluted drinking water remediation applications.

To achieve visualized, dynamic quantitative monitoring of Microthrix parvicella surface hydrophobicity during activated sludge filamentous bulking and to overcome the limitations of traditional methods in accurately characterizing filamentous bacteria hydrophobicity, seven fluorescent probes with distinct polarities were designed and synthesized based on the specific binding mechanism between lipid substrates and lipase. Results showed probe dipole moment and binding energy are key factors affecting staining efficiency. Probes with small dipole moments (< 10 Debye) and high binding energies (<-9.0 kcal/mol) stably bind to nonpolar regions of the cell membrane and lipase, maintaining staining ability but exhibiting low sensitivity to hydrophobicity changes. Probes with large dipole moments (> 20 Debye) and low binding energies (>-9.0 kcal/mol) were sensitive but lost staining ability rapidly as hydrophobicity decreased. Moderate-parameter probes exhibit a balance between stability and sensitivity, with fluorescence intensity consistent with M. parvicella growth cycle and Sludge Volume Index (SVI), thereby accurately reflecting hydrophobicity fluctuations during bulking.