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A Red Emitting Fluorescent Probe for Imaging Mitochondrial Hydrogen Polysulfide in Living Cells and Tissues
摘要： Hydrogen polysulfide (H2Sn) has attracted increasing attention since H2Sn instead of H2S has been shown to be the actual signaling molecule in physiological and pathological processes. Thus, developing accurate and sensitive assays for H2Sn detection is urgently needed in biological science. In this work, we developed a red emitting mitochondria-targeting fluorescent probe, HQO-PSP, that is capable of tracking H2Sn. With low cytotoxicity, good selectively and high sensitively, HQO-PSP was able to detect H2Sn in living cells. Furthermore, we also demonstrated that HQO-PSP could also be successfully applied to recognize H2Sn in living tissues.
关键词： Hydrogen polysulfide,Fluorescent probe,Lung tissues,Living cells
更新于2025-11-19 16:46:39
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Polysiloxane-based Hyperbranched Fluorescent Materials Prepared by Thiol-ene “Click” Chemistry as Potential Cellular Imaging Polymers
摘要： Hyperbranched polymers have attracted increasing interest due to their unique properties which possess excellent RI and thermal stability, and have been widely used in fields of drug delivery, catalysts, liquid crystal and so on. Herein, polysiloxane-based hyperbranched fluorescent materials (P1 and P2) were synthesized by thiol-ene “click” chemistry. Then, novel polysiloxane-based hyperbranched fluorescent materials (P1-Ln3+) has been prepared by rare earth ions coordination. In view of the splendid fluorescence characteristics and favorable stability of P1-Ln3+, it has been applied in biological imaging. P1-Ln3+ has gained commendable applications in bioimaging.
关键词： Fluorescence materials,Living cells imaging,Hyperbranched polymers,Thiol-ene "click" chemistry,Coordination,Rare earth ions
更新于2025-09-23 15:23:52
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Raman Spectroscopic Analysis of Signaling Molecules–Dopamine Receptors Interactions in Living Cells
摘要： The selective interaction of signaling compounds including neurotransmitters and drugs with the dopamine receptors (DARs) is extremely important for the treatment of neurodegenerative diseases. Here, we report a method to probe the selective interactions of signaling compounds with D1 and D2 DARs in living cells using the combined approach of theoretical calculation and surface-enhanced Raman spectroscopy (SERS). When signaling compounds such as DA, amphetamine, methamphetamine, and methylenedioxypyrovalerone interact with D1 dopamine receptors (DRD1), the intracellular cyclic adenosine monophosphate (cAMP) level is increased. However, the intracellular level of cAMP is decreased when D2 dopamine receptors (DRD2) interact with the abovementioned signaling compounds. In our experiments, we have internalized the silica-coated silver nanoparticles (AgNP@SiO2) in living cells to adsorb biologically generated cAMP which was probed by using SERS. Besides adsorptions of cAMP, AgNP@SiO2 has a crucial role for the enhancement of Raman cross section of the samples. We observed the characteristic SERS peaks of cAMP when DRD1-overexpressed cells interact with the signaling compounds; these peaks were not observed for other cells including DRD2-overexpressed and DRD1?DRD2-coexpressed cells. Our experimental approach is successful to probe the intracellular cAMP and characterize the selectivity of signaling compounds to different types of DARs. Furthermore, our experimental approach is highly capable for in vivo studies because it can probe intracellular cAMP using a low input power of incident laser without significant cell damage. Our experimental results and density functional theory calculations showed that 780 and 1503 cm?1 are signature Raman peaks of cAMP. The SERS peak at 780 cm?1 is associated with C?O, C?C, and C?N stretching and symmetric and asymmetric bending of two O?H bonds of cAMP, whereas the SERS peak at 1503 cm?1 is contributed by the O9?H3 bending mode.
关键词： cyclic adenosine monophosphate,living cells,signaling compounds,dopamine receptors,surface-enhanced Raman spectroscopy
更新于2025-09-23 15:21:21
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A Turn-On Fluorescent Probe for Sensitive Detection of Cysteine in a Fully Aqueous Environment and in Living Cells
摘要： We reported here a turn-on fluorescent probe (1) for the detection of cysteine (Cys) by incorporating the recognition unit of 2,4-dinitrobenzenesulfonyl ester (DNBS) to a coumarin derivative. The structure of the obtained probe was confirmed by NMR and HRMS techniques. The probe shows a remarkable fluorescence off-on response (～52-fold) by the reaction with Cys in 100% aqueous buffer. The sensing mechanism was verified by the HPLC test. Probe 1 also displays high selectivity towards Cys. The detection limit was calculated to be 23 nM. Moreover, cellular experiments demonstrated that the probe is highly biocompatible and can be used for monitoring intracellular Cys.
关键词： living cells,aqueous environment,fluorescent probe,turn-on,cysteine
更新于2025-09-19 17:15:36
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Monodisperse Au@Ag core-shell nanoprobes with ultrasensitive SERS-activity for rapid identification and Raman imaging of living cancer cells
摘要： The rapid identification of living cancer cells is highly crucial for cancer diagnosis, prognosis, and treatment monitoring. However, it is a great challenge to develop an effective way for rapid identification and imaging of cancer cells in a living state. Moreover, synthesis of monodisperse nanoparticles (NPs) with high sensitive surface-enhanced Raman scattering (SERS) activity is also a tough work. Herein, we creatively reported a convenient method to synthesize the novel NPs as the substrate of SERS sensors, which possessed a gold nanobipyramid core and silver nanorod shell. These gold nanobipyramid core and silver nanorod shell NPs (Au NBP@Ag NRs) were further modified with 4-mercaptobenzoicacid (4-MBA, Raman reporter molecule) and then conjugated with reduced bovine serum albumin (rBSA) and folic acid (FA) on their surfaces, to finally acquire Au NBP@Ag NR-MBA-rBSA-FA nanoprobes. In this system, With the enhancement factor (EF) of Au NBP@Ag NRs was about 4 × 10^7, it could significantly enhance Raman signal for Raman reporter molecules, and 4-MBA molecules performed high SERS signals based on their structures; the nanoprobes have favorable specificity and biocompatibility owing to the modification of rBSA which effectively avoided the nonspecific attachment of non-targeted cells. Moreover, the obtained SERS nanoprobes have excellent sensitivity for gastric cancer cells (MGC-803 cells) due to the conjugation of folic acid. Thus, the finally obtained Au NBP@Ag NR-MBA-rBSA-FA nanoprobes possess excellent detection efficiency for living MGC-803 cells. Therefore, our synthesized nanoprobes exhibit ultrasensitive SERS-activity, excellent specificity and superior cancer cells targeting ability, which could be applied for rapid identification and Raman imaging of living cancer cells via the SERS signal detection of the nanoprobes.
关键词： SERS,Au NBP@Ag NR-MBA-rBSA-FA nanoprobes,Living cells imaging,MGC-803
更新于2025-09-19 17:15:36
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Green emitted CdSe@ZnS quantum dots for FLIM and STED imaging applications
摘要： Inorganic quantum dots (QDs) have excellent optical properties, such as high fluorescence intensity, excellent photostability and tunable emission wavelength, etc., facilitating them to be used as labels and probes for bioimaging. In this study, CdSe@ZnS QDs are used as probes for Fluorescence lifetime imaging microscope (FLIM) and stimulated emission depletion (STED) nanoscopy imaging. The emission peak of CdSe@ZnS QDs centered at 526 nm with a narrow width of 19 nm and the photoluminescence quantum yield (PLQY) was 64%. The QDs presented excellent anti-photobleaching property which can be irradiated for 400 min by STED laser with 39.8 mW. The lateral resolution of 42.0 nm is demonstrated for single QDs under STED laser (27.5 mW) irradiation. Furthermore, the CdSe@ZnS QDs were for the first time used to successfully label the lysosomes of living HeLa cells and 81.5 nm lateral resolution is obtained indicating the available super-resolution applications in living cells for inorganic QD probes. Meanwhile, Eca-109 cells labeled with the CdSe@ZnS QDs was observed with FLIM, and their fluorescence lifetime was around 3.1 ns, consistent with the in vitro value, suggesting that the QDs could act as a satisfactory probe in further FLIM-STED experiments.
关键词： CdSe@ZnS QDs,living cells,STED,FLIM
更新于2025-09-19 17:13:59
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Rapid, facile, reagentless, and room-temperature conjugation of monolayer MoS2 nanosheets with dual-fluorophore-labled flares as Nanoprobes for ratiometric sensing of TK1 mRNA in living cells
摘要： Direct loading of fluorophore-labeled DNA molecules (named as flares) on gold nanoparticles (AuNPs) is a controllable and straightforward approach for intracellular imaging of target DNA molecules. However, the modification of AuNPs with flares requires a tedious and time-consuming procedure, additional reagents, or adenosine-rich DNA molecules. Here, we developed a rapid, simple, reagentless, and room-temperature approach for the modification of monolayer molybdenum disulfide nanosheets (M-MoS2 NSs) with dual-fluorophore-labeled flares, which were implemented for ratiometric imaging of TK1 mRNA in living cells. The duplexes were prepared by hybridizing thiolated single-stranded DNA (ssDNA) to 6-carboxyfluorescein (FAM)- and 5-carboxytetramethylrhodamine (TAMRA)-labeled flares. Fabrication of the nanoflares was conducted by conjugating the formed duplexes to the surface sulfur vacancy sites of the M-MoS2 NSs. The time for preparing the nanoflares was found to be completed within 1 h. In the nanoflares, FAM stays away from TAMRA, leading to inefficient fluorescence resonance energy transfer (FRET). The presence of perfectly matched DNA (DNApm) molecules induces the liberation of the flares from the nanoflares. The liberated flares fold into hairpin-shaped structures, causing high FRET efficiency from FAM to TAMRA and efficient FAM-TAMRA static quenching. Following this mechanism, the nanoflares provided an effective platform for ratiometric sensing of DNApm molecules with the limit of detection (at a signal-to-noise ratio of 3) of 8 nM and the linear range of 25?500 nM. Confocal microscopy experiments demonstrated that the nanoflares can be used to ratiometrically image TK1 mRNA in HeLa and MCF-7 cells.
关键词： ratiometric sensing,monolayer MoS2 nanosheets,TK1 mRNA,dual-fluorophore-labeled flares,living cells
更新于2025-09-16 10:30:52
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The in vivo mechanics of the magnetotactic backbone as revealed by correlative FLIM-FRET and STED microscopy
摘要： Protein interaction and protein imaging strongly benefit from the advancements in time-resolved and superresolution fluorescence microscopic techniques. However, the techniques were typically applied separately and ex vivo because of technical challenges and the absence of suitable fluorescent protein pairs. Here, we show correlative in vivo fluorescence lifetime imaging microscopy F?rster resonance energy transfer (fLiM-fRet) and stimulated emission depletion (SteD) microscopy to unravel protein mechanics and structure in living cells. We use magnetotactic bacteria as a model system where two proteins, MamJ and MamK, are used to assemble magnetic particles called magnetosomes. The filament polymerizes out of MamK and the magnetosomes are connected via the linker MamJ. Our system reveals that bacterial filamentous structures are more fragile than the connection of biomineralized particles to this filament. More importantly, we anticipate the technique to find wide applicability for the study and quantification of biological processes in living cells and at high resolution.
关键词： FLIM-FRET,living cells,magnetotactic bacteria,STED microscopy,protein mechanics
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Live Multi-Color Coherent Raman Imaging Enabled by Millisecond Wavelength Tuning
摘要： We present multi-color coherent Raman imaging (CRI) with a frame rate of 8 Hz and rapid wavelength tuning within only 5 ms between successive images, enabled by a novel fiber optical parametric oscillator (FOPO). In CRI the limited tuning speed of conventional laser systems (>1 s) prevents the acquisition of successive images per second at more than one vibrational resonance and is considered as a bottleneck for multi-color assessments of medical specimen and rapidly evolving samples, such as living cells. Recent approaches to CRI with wavelength switching on a timescale of (sub-) milliseconds were based on two synchronized oscillators [1], being limited to two resonances, and parallel laser amplifiers [2] or spectral focusing techniques [3], both the latter with a limited tuning bandwidth of less than 300 cm-1. In contrast, the energy difference of the pump and Stokes pulses, emitted by the here presented FOPO, is tunable across the wide spectral range between 865 and 3050 cm-1 within only 5 ms. Assuming an equal time span for tuning and acquisition, up to 100 user-selectable vibrational components could be imaged per second, when imaging with 100 frame/s. The rapid tuning was achieved by a novel tuning concept for OPOs, based on the dispersive matching of the repetition frequency change of the pump pulses to the associated repetition frequency change of the resonant signal pulses in the FOPO. No alteration of the FOPO, e.g., via a mechanical delay line [4], was required for tuning the signal wavelength and the light source could be composed of all-spliced fiber components. Compared to previously presented FOPOs, the system runs at a high repetition rate of 40 MHz. The pump and Stokes pulses exhibit equal durations of 7 ps and an average power of 500 and 200 mW, respectively. As a first proof-of concept of the CRI capabilities, Fig. 1 shows three images of a sample consisting of water, oil and beads of PMMA and PS, taken successively with an acquisition time of 125 ms for each frame, limited only by the sampling rate of our detection setup. The energy difference was tuned in a frame-by-frame manner between 2850, 2950 and 3050 cm-1 in a time of 5 ms, a negligible time span compared to the acquisition time.
关键词： vibrational resonance,living cells,medical specimen,rapid wavelength tuning,fiber optical parametric oscillator,multi-color coherent Raman imaging
更新于2025-09-12 10:27:22
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Quantum Dots for Monitoring Choline Consumption Process of Living Cells via an Electrostatic Force-Mediated Energy Transfer
摘要： In this work, a ratiometric nanoprobe CdS/ZnS-FB was designed for H2O2 detection based on FRET assay. Furthermore, CdS/ZnS-FB could work for detecting choline (Ch) and acetylcholine (ACh) since H2O2 is the enzyme cascade reaction product. Significantly, choline consumption could also be quantitatively measured by monitoring FRET ratio (I522 /I426). Thus, the biosensor could be applied as a universal tool for the detection of choline consumption of living cells, which provides a good potential for the applications in detecting chemical transmitter and cancer diagnosis.
关键词： H2O2,living cells,enzyme cascade reaction,FRET,quantum dots
更新于2025-09-11 14:15:04