- 标题
- 摘要
- 关键词
- 实验方案
- 产品
过滤筛选
- 2018
- electromagnetic pulse
- cell proliferation
- cell membrane permeability
- cell response to electromagnetic stress
- apoptosis
- cancer therapy
- necrosis
- Intelligent Medical Engineering
- V.N. Karazin Kharkiv National University
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Measuring the interaction of transcription factor Nrf2 with its negative regulator Keap1 in single live cells by an improved FRET/FLIM analysis
摘要： Transcription factor NF-E2 p45-related factor 2 (Nrf2) and its principal negative regulator, Kelch-like ECH-associated protein 1 (Keap1), comprise a molecular effector and sensor system that robustly responds to perturbations of the cellular redox homeostasis by orchestrating a comprehensive cytoprotective program. Under homeostatic conditions, Nrf2 is a short-lived protein, which is targeted for ubiquitination and proteasomal degradation. Upon encounter of electrophiles, oxidants or pro-inflammatory stimuli, the cysteine sensors in Keap1 are chemically modified, rendering Keap1 unable to target Nrf2 for degradation, and consequently leading to accumulation of the transcription factor and enhanced transcription of cytoprotective genes. Detailed understanding of the protein-protein interactions between Nrf2 and Keap1 has been achieved by use of various in vitro systems, but few assays are available to assess these interactions in the context of the living cell. We previously developed an imaging-based FLIM/FRET methodology to visualise and measure the interaction between Nrf2 and Keap1 in single cells. Here, our goal was to improve this methodology in order to increase throughput and precision, and decrease cell-to-cell variability. To eliminate the possibility of orientation bias, we incorporated a flexible linker between Keap1 and the FRET acceptor fluorescent protein tag. To ensure the correct image capture of Nrf2 fused to the FRET donor fluorescent protein tag, we matched the maturation time of the fluorescent tag to the half-life of the endogenous Nrf2, by using sfGFP as the FRET donor. Using a global binning approach increased the assay throughput, whereas including the measured Instrument Response Function in the analysis improved precision. The application of this methodology revealed a strong covariation of the results with the expression level of the acceptor. Taking the acceptor level into account circumvented cell-to-cell variability and enhanced sensitivity of the measurements of the Keap1-Nrf2 interaction in live cells.
关键词： FRET,live cell imaging,fluorescence lifetime,FLIM,sfGFP,protein-protein interaction,global binning,Keap1,Instrument Response Function,Nrf2
更新于2025-11-21 11:08:12
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A novel near-infrared light responsive 4D printed nanoarchitecture with dynamically and remotely controllable transformation
摘要： Four-dimensional (4D) printing is an emerging and highly innovative additive manufacturing process by which to fabricate pre-designed, self-assembly structures with the ability to transform over time. However, one of the critical challenges of 4D printing is the lack of advanced 4D printing systems that not only meet all the essential requirements of shape change but also possess smart, dynamic capabilities to spatiotemporally and instantly control the shape-transformation process. Here, we present a facile 4D printing platform which incorporates nanomaterials into the conventional stimuli-responsive polymer, allowing the 4D printed object to achieve a dynamic and remote controlled, on-time and position shape transformation. A proof-of-concept 4D printed brain model was created using near-infrared light (NIR) responsive nanocomposite to evaluate the capacity for controllable 4D transformation, and the feasibility of photothermal stimulation for modulating neural stem cell behaviors. This novel 4D printing strategy can not only be used to create dynamic 3D patterned biological structures that can spatiotemporally control their shapes or behaviors of transformation under a human benign stimulus (NIR), but can also provide a potential method for building complex self-morphing objects for widespread applications.
关键词： brain,4D printing,dynamically and remotely controllable,neural stem cell,near-infrared light responsive,graphene
更新于2025-11-21 11:08:12
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A ratiometric fluorescence probe based on a novel recognition mechanism for monitoring endogenous hypochlorite in living cells
摘要： A ratiometric fluorescence probe (named ZOC) for the fast detection of HClO/ClO- was constructed by coumarin (donor) and pyridinium (acceptor) based on Forster resonance energy transfer (FRET) and intramolecular charge transfer (ICT) platform. ZOC possessed red emission signal (610 nm), large Stocks shift (190 nm), high energy transfer efficiency (95.3%), high selectivity and sensitivity, low detection limit (25 nM), wider detection range (from 25 nM to 30 μM), rapid response (within 13 S), and good biocompatibility. It was very interesting that the recognition mechanism involved a new organic reaction in which olefin double bond reacted first with HClO/ClO- regioselectively, followed by cyclization. ZOC was successfully used to the real time detection of endogenous HClO/ClO- in RAW 264.7 cells.
关键词： Hypochlorous acid/hypochlorite,Probe,Cell image,Ratiometric fluorescence,New mechanism
更新于2025-11-21 11:08:12
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A novel peptide-based fluorescent chemosensor for Cd(II) ions and its applications in bioimaging
摘要： Nowadays, it is of great significance to develop a novel fluorescent chemosensor for Cd(II) ions detection with cost-effective, rapid, facile and applicable to environment and biological milieus. Herein, we report a new peptide-based fluorescent chemosensor DSC (Dan-Ser-Cys-NH2) based on dipeptide (Ser-Cys-NH2) conjugated with dansyl group, which was synthesized using solid phase peptide synthesis (SPPS) technology. As designed, DSC exhibited fluorescent “turn-on” response for Cd2+ in 100% aqueous solution over a wide range of pH values based on photoinduced electron transfer (PET). The stoichiometry binding of DSC and Cd2+ was determined to be 2:1 by Job’s plot and ESI-MS analysis. Furthermore, DSC showed highly sensitive for Cd2+ and a low detection limit of 13.8 nM. What's more, DSC has cell permeability and low cytotoxicity, and fluorescence imaging experiments demonstrated that DSC was capable of monitoring Cd2+ in living HK2 cells by confocal microscopy.
关键词： Fluorescent chemosensor,Cell imaging,Cd(II) ions,Dansyl group,Dipeptide
更新于2025-11-21 11:08:12
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A sequential and reversibility fluorescent pentapeptide probe for Cu(II) ions and hydrogen sulfide detections and its application in two different living cells imaging
摘要： In this study, we report a sequential and reversibility fluorescent probe (DP5) based on pentapeptide conjugated with dansyl groups using the solid phase peptide synthesis (SPPS) technology. DP5 showed immediate “turn off” response toward Cu2+ ions at an excitation wavelength of 330 nm with detection limits of 23.5 nM. The 2:1 binding ratio between DP5 and Cu2+ were confirmed using Job's plot method and fluorescence titration study, and DP5-Cu complex was observed with an association constant of 6.76 × 108 M?2. As designed, DP5-Cu complex as a promising analytical probe exhibited highly selective for H2S detection in aqueous solutions. The detection limit for H2S was obtained to be 17.2 nM, and lower than EPA and WHO guidelines. In addition, the reversibility and cyclicity were imparted to the DP5 during the detection of Cu2+ and H2S, and cycle effect is very good. Furthermore, DP5 displayed better biocompatibility and low biotoxicity, and sequential fluorescence “on-off-on” responses of DP5 to Cu2+ and H2S were successfully applied in two different living cells.
关键词： Cu2+ ions,Pentapeptide,Fluorescent probe,Cell imaging,Hydrogen sulfide,Aqueous solutions
更新于2025-11-21 11:08:12
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Perylenequinone-based “turn on” fluorescent probe for hydrogen sulfide with a high sensitivity in living cells
摘要： Hydrogen sulfide (H2S) is a kind of gaseous signal molecule in many physiological processes. In order to detect H2S, a novel “turn on” fluorescent probe 6,12-dihydroxyperylene-1,7-dione (DPD) was designed and synthesized. The probe DPD is fluorescence silence, while the addition of H2S induces an obvious green fluorescence with an obvious color change from dark blue to yellow-green. The probe shows excellent selectivity, fast response (2.5 minutes) and linear curve (0-90 μM) in wide effective pH range (4-10). Competition experiments are also revealed in corresponding studies and the detection limit is 3.6 μM. The response mechanism is proved to be the reduction of the probe by H2S, which is confirmed by 1H NMR. Furthermore, through the fluorescence turn-on signal toward H2S in Hela cells, probe DPD was successfully applied to monitor H2S in living Hela cells.
关键词： hydrogen sulfide,probe,fluorescence imaging,cell imaging,perylenequinone
更新于2025-11-21 11:08:12
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A new FRET-based ratiometric fluorescence probe for hypochlorous acid and its imaging in living cells
摘要： A novel ratiometric fluorescence probe for hypochlorous acid was constructed by coumarin and pyridinium fluorophore based on the Forster resonance energy transfer (FRET) and intramolecular charge transfer (ICT) platform. In this ICT/FRET system, the energy transfer efficiency is high to 94.3%. Moreover, the probe could respond to hypochlorous acid with high selectivity and sensitivity, and exhibited a large Stokes shift. It was interesting to find that the probe could recognize hypochlorous acid via a new mechanism, in which the a -position of carbonyl group was oxidized to form a diketone derivative. More importantly, the probe was successfully applied to the ratiometric imaging of both exogenous and endogenous hypochlorous acid in living RAW 264.7 cells, with low toxicity and high photo-stability.
关键词： New reaction mechanism,FRET,Hypochlorous acid,Fluorescence probe,Cell image,Ratiometric
更新于2025-11-21 11:08:12
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AIE active fluorescent organic nanoaggregates for selective detection of phenolic-nitroaromatic explosives and cell imaging
摘要： Development of organic nanoparticles with high fluorescence, good biocompatibility along with strong resistance to photobleaching through simple synthetic routes is important for diverse applications such as sensing and bioimaging. Herein, we present the development of a pyrene excimer nanoaggregate which shows aggregation induced emission (AIE) effect in a solvent mixture of THF and water. The pyrene based fluorescent probe, dimethyl-5-(pyren-1-ylmethyleneamino)isophthalate (5-DP) was synthesized through a simple single step condensation reaction from inexpensive reagents. The photophysical studies of nanoaggregated system further corroborates the AIE active behavior of 5-DP probe at different water fractions (?w = 0% to 90%), where the hydrogen bonding interaction between imine and water molecules led to suppression of photoinduced electron transfer (PET) inducing significant enhancement in fluorescence. The highly photostable nanoaggregates were explored as a selective fluorescence “turn off” sensor for phenolic nitroaromatics and the chemo-selectivity was highly pronounced for 2,4,6-trinitrophenol (picric acid), that showed efficient quenching in aqueous as well as solid phase, with a detection limit of 10 nM in aqueous medium. The quenching efficiency of the nanoaggregates can be ascribed to a combination of factors including efficient fluorescence resonance energy transfer, inner filter effect and coulombic interaction between picric acid and the aggregated probe molecules. Further, random aggregation of the pyrene derivative could be controlled for the formation of fluorescent spherical nanoparticles using Pluoronics P-123 block copolymers as encapsulating agents. The resulting composite could be used as a neoteric cell imaging probe with significantly less cytotoxicity, thus showing their potential biological applications.
关键词： aggregation induced emission,electron transfer,explosive detection,cell imaging,Fluorescent organic nanoaggregates
更新于2025-11-21 11:03:13
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Transparent Platinum Counter Electrode Prepared by Polyol Reduction for Bifacial, Dye-Sensitized Solar Cells
摘要： Pt catalytic nanoparticles on F-doped SnO2/glass substrates were prepared by polyol reduction below 200 °C. The polyol reduction resulted in better transparency of the counter electrode and high power-conversion efficiency (PCE) of the resultant dye-sensitized solar cells (DSSCs) compared to conventional thermal reduction. The PCEs of the DSSCs with 5 μm-thick TiO2 photoanodes were 6.55% and 5.01% under front and back illumination conditions, respectively. The back/front efficiency ratio is very promising for efficient bifacial DSSCs.
关键词： dye-sensitized solar cell,platinum,bifacial,ethylene glycol,counter electrode
更新于2025-11-21 11:01:37
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Liquid Crystal-Induced Myoblast Alignment
摘要： The ability to control cell alignment represents a fundamental requirement toward the production of tissue in vitro but also to create biohybrid materials presenting the functional properties of human organs. However, cell cultures on standard commercial supports do not provide a selective control on the cell organization morphology, and different techniques, such as the use of patterned or stimulated substrates, are developed to induce cellular alignment. In this work, a new approach toward in vitro muscular tissue morphogenesis is presented exploiting liquid crystalline networks. By using smooth polymeric films with planar homogeneous alignment, a certain degree of cellular order is observed in myoblast cultures with direction of higher cell alignment corresponding to the nematic director. The molecular organization inside the polymer determines such effects since no cell organization is observed using homeotropic or isotropic samples. These findings represent the first example of cellular alignment induced by the interaction with a nematic polymeric scaffold, setting the stage for new applications of liquid crystal polymers as active matter to control tissue growth.
关键词： liquid crystalline alignments,liquid crystalline network,cell alignment,biomaterials,muscular tissue engineering
更新于2025-11-21 11:01:37