A multifunctional fluorescent sensor based on a cyclen-appended BINOL derivative (R-1) was synthesized and characterized. It can display on–off-type fluorescence change with high selectivity toward ...Cu(II) among 19 metal ions in 100% aqueous solution. Furthermore, the in situ generated R-1–Cu(II) ensemble could recover the quenched fluorescence upon the addition of sulfide anion resulting in a off–on-type sensing with a detection limit of micromolar range in the same medium. No interference was observed from other biothiols and anions, including GSH, l-Cys, DTT, and sulfates, making it a highly sensitive and selective sulfide probe.
Fluorescence spectroscopy and microscopy have been utilized as tools in membrane biophysics for decades now. Because phospholipids are non-fluorescent, the use of extrinsic membrane probes in this ...context is commonplace. Among the latter, 1,6-diphenylhexatriene (DPH) and its trimethylammonium derivative (TMA-DPH) have been extensively used. It is widely believed that, owing to its additional charged group, TMA-DPH is anchored at the lipid/water interface and reports on a bilayer region that is distinct from that of the hydrophobic DPH. In this study, we employ atomistic MD simulations to characterize the behavior of DPH and TMA-DPH in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and POPC/cholesterol (4:1) bilayers. We show that although the dynamics of TMA-DPH in these membranes is noticeably more hindered than that of DPH, the location of the average fluorophore of TMA-DPH is only ~3–4Å more shallow than that of DPH. The hindrance observed in the translational and rotational motions of TMA-DPH compared to DPH is mainly not due to significant differences in depth, but to the favorable electrostatic interactions of the former with electronegative lipid atoms instead. By revealing detailed insights on the behavior of these two probes, our results are useful both in the interpretation of past work and in the planning of future experiments using them as membrane reporters.
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•DPH and TMA-DPH were simulated in both pure POPC and POPC/cholesterol bilayers.•We provided insights on the behavior of TMA-DPH and its differences to that of DPH.•The effects of both probes on the bilayer properties are globally small.•TMA-DPH has a more superficial location than DPH, albeit by only ~0.3–0.4nm.•Motions of TMA-DPH are hindered because of electrostatic interactions with lipids.
A novel fluorescent receptor L was synthesized by Schiff base condensation of 1-pyrenemethylamine with the vitamin B
cofactor pyridoxal. The receptor L is highly selective and sensitive towards Zn
...ions among other tested metal ions. Upon interaction with Zn
, the receptor L showed a distinct fluorescence enhancement at 485 nm due to the excimer formation leading to the fluorescent colour change from blue to bluish-green. Subsequently, when the in situ generated ZnL
complex interacted with various anions and amino acids, the addition of H
PO
and cysteine reinstated the fluorescence of the receptor L due to the demetalation of Zn
from the ZnL
complex. Accordingly, the receptor L was developed for the highly selective, specific and sensitive detection of three important bioactive analytes, i.e., Zn
, H
PO
and cysteine with a detection limit down to 2.3 × 10
M, 2.18 × 10
M and 1.59 × 10
M, respectively. Additionally, the receptor L was applied to the detection of intracellular Zn
ions in live HeLa cells.
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•Fluorinated polymer NPs with core-shell type morphology show no dye leakage.•Refractive index of fluorescent NPs hence their use for the confocal microscopy study.•Structure of dye ...has an impact on the zeta potential of fluorinated acrylate Nps.
Fluorescent core-shell particles are used as versatile fluorophores in confocal microscopy based image analysis and as a colloidal model system to study short and long-range interactions. Bright and stable microspherical probes are proposed as promising materials, especially in bioimaging applications. The release of dyes from fluorescent polymer microspheres is undesirable. Covalent linking of dyes within polymeric spheres during the polymerization process can solve the problem of dye leaching. This requires, e.g. the introduction of reactive groups into the dyes. Its more lipophilic ester-ether derivatives considerably reduced fluorescence. The fluorescent quantum yield of prepared nanoparticles was determined to be below 10%. As-prepared nanoparticles exhibited a low refractive index (1.293–1.349), hence their use is recommended. Scanning electron microscope (SEM) images and the fluorescence correlation spectroscopy (FCS) measurements confirmed high polydispersity of synthesized particles (40–230 nm), and are in agreement with the dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) results (hydrodynamic diameters 203 ± 9, 548 ± 50, 146 ± 2 nm). The zeta potential of fluorescent 1H,1H-heptafluoro-n-butyl methacrylate (HFBMA) shell nanoparticles (NPs) with propargyl ether-esters, 2-methyl allyl ether-esters and allyl ether-esters of fluorescein was -44.5,-14, -44.7 mV, respectively. The values are different despite the slight difference in the structure of ester-ether derivatives.
A series of pyrene-based silicon-containing polymer fluorescent materials with high selectivity and sensitivity to TNP and potential application in cell imaging.
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•We designed and ...synthesized two kinds of silicone-containing polymer fluorescent materials (linear polymer and network polymer).•We explored their differences in the application of nitro-compound detection.•The fluorescent materials have been prepared to paper sensors with high sensitivity to 2,4,6-trinitrophenol (TNP) and can be applied in cell imaging.
The simple and rapid detection of chemical explosives is important for life safety and social stability, and correlative explorations of new material or system have attracted more and more attention. Two kinds of pyrene-based polymers (PyM and PyP) were prepared by Heck-coupling reaction in this work. The obtained fluorescent materials exhibited excellent fluorescence properties and showed high selectivity and sensitivity for the detection of trinitrophenol (TNP). Furthermore, a portable paper sensor based on this material for fast detection of TNP was explored. The obtained fluorescent materials were further applied in cell imaging. The construction strategy of fluorescent materials involved in this paper expands a new perspective for the design of fluorescent probes for detecting nitroaromatic compounds.
•A nanocomposite of black phosphorus quantum dots wrapped with MnO2 (BPQDs@MnO2) was constructed.•The quenching performance of BPQDs by MnO2 was investigated.•Glutathione (GSH) was determined by the ...activatable fluorescence of BPQDs@MnO2.•BPQDs@MnO2 exhibited great potentials in the fluorescence/MRI bimodal imaging of intracellular GSH.
Glutathione (GSH) is closely related to many physiological processes, the sensitive determination of GSH is significant to the diagnostic and treatment of the specific diseases. In this work, an activatable bimodal imaging and determination strategy of GSH is proposed based on the nanocomposite of black phosphorus quantum dots (BPQDs) wrapped with manganese dioxide nanosheets (BPQDs@MnO2). The quenched fluorescence of BPQDs can be recovered with the addition of GSH, as a result of the reduction of MnO2. The BPQDs@MnO2 appears a linearly activatable fluorescence to the addition of GSH from 0.1 μM to 60 μM with a limit of detection of 35 nM (3σ/s). As the Mn2+ produced by the reduction of MnO2 is a good magnetic resonance imaging (MRI) contrast agent, the BPQDs@MnO2 is applied to the fluorescence/MRI bimodal imaging of intracellular GSH. MTT experiments prove the good biocompatibility of BPQDs@MnO2, and different kinds of cells are used to demonstrated that bimodal imaging intensity of cells incubated with BPQDs@MnO2 was dependent on the concentration of intracellular GSH. This strategy provided a new method for the activatable determination of GSH, and offered a promising platform for fluorescence/MRI bimodal imaging of GSH in living cells.
The ovary surface epithelium (OSE) undergoes ovulatory tear and remodelling throughout life. Resident stem cells drive such tissue homeostasis in many adult epithelia, but their existence in the ...ovary has not been definitively proven. Lgr5 marks stem cells in multiple epithelia. Here we use reporter mice and single-molecule fluorescent in situ hybridization to document candidate Lgr5(+) stem cells in the mouse ovary and associated structures. Lgr5 is broadly expressed during ovary organogenesis, but becomes limited to the OSE in neonate life. In adults, Lgr5 expression is predominantly restricted to proliferative regions of the OSE and mesovarian-fimbria junctional epithelia. Using in vivo lineage tracing, we identify embryonic and neonate Lgr5(+) populations as stem/progenitor cells contributing to the development of the OSE cell lineage, as well as epithelia of the mesovarian ligament and oviduct/fimbria. Adult Lgr5(+) populations maintain OSE homeostasis and ovulatory regenerative repair in vivo. Thus, Lgr5 marks stem/progenitor cells of the ovary and tubal epithelia.
OBJECTIVES: To prepare fluorescent carbon dots for loading cationic anticancer drug through donor-quenched nanosurface energy transfer in visible sensing of drug release. RESULTS: Highly fluorescent ...carbon dots (CDs) were prepared by a facile hydrothermal approach from citric acid and o-phenylenediamine. The obtained CDs showed a high quantum yield of 46 % and exhibited good cytocompatibility even at 1 mg/ml. The cationic anticancer drug doxorubicin (DOX) can be loaded onto the negatively charged CDs through electrostatic interactions. Additionally, the fluorescent CDs feature reversible donor-quenched mode nanosurface energy transfer. When loading the energy receptor DOX, the donor CDs’ fluorescence was switched “off”, while it turned “on” again after DOX release from the surface through endocytic uptake. CONCLUSIONS: Most DOX molecules were released from the CDs after 6 h incubation and entered cell nuclear region after 8 h, suggesting the drug delivery system may have potential for visible sensing in drug release.
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