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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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Opto-thermally Excited Fabry-Perot Resonance Frequency Behaviors of Clamped Circular Graphene Membrane
摘要： An opto-thermally excited optical fiber Fabry-Perot (F-P) resonant probe with suspended clamped circular graphene diaphragm is presented in this paper. Then, the dependence of resonance frequency behaviors of graphene diaphragm upon opto-mechanical factors including membrane properties, laser excitation parameters and film boundary conditions are investigated via COMSOL Multiphysics simulation. The results show that the radius and thickness of membrane will linearly affect the optical fiber light-induced temperature distribution, thus resulting in rapidly decreasing resonance frequency changes with the radius-to-thickness ratio. Moreover, the prestress can be regulated in the range of 108 Pa to 109 Pa by altering the environmental temperature with a scale factor of 14.2 MPa/K. It is important to note that the availability of F-P resonant probe with a defective clamped circular graphene membrane can be improved notably by fabricating the defected circular membrane to a double-end clamped beam, which gives a broader perspective to characterize the resonance performance of opto-thermally excited F-P resonators.
关键词： opto-thermal actuation,graphene membrane,Fabry-Perot resonator,resonance frequency simulation
更新于2025-11-28 14:23:57
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Fluorescent membrane markers elucidate the association of Borrelia burgdorferi with tick cell lines
摘要： This study aimed to describe the association of Borrelia burgdorferi s.s. with ixodid tick cell lines by flow cytometry and fluorescence and confocal microscopy. Spirochetes were stained with a fluorescent membrane marker (PKH67 or PKH26), inoculated into 8 different tick cell lines and incubated at 30°C for 24 h. PKH efficiently stained B. burgdorferi without affecting bacterial viability or motility. Among the tick cell lines tested, the Rhipicephalus appendiculatus cell line RA243 achieved the highest percentage of association/internalization, with both high (90%) and low (10%) concentrations of BSK-H medium in tick cell culture medium. Treatment with cytochalasin D dramatically reduced the average percentage of cells with internalized spirochetes, which passed through a dramatic morphological change during their internalization by the host cell as observed in time-lapse photography. Almost all of the fluorescent bacteria were seen to be inside the tick cells. PKH labeling of borreliae proved to be a reliable and valuable tool to analyze the association of spirochetes with host cells by flow cytometry, confocal and fluorescence microscopy.
关键词： Fluorescent membrane marker,Tick cell lines,Borrelia burgdorferi,Phagocytosis
更新于2025-11-21 11:24:58
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Direct Three-Dimensional Visualization of Membrane Fouling by Confocal Laser Scanning Microscopy
摘要： Membrane-based separation is an important technique for removing emulsified oil from water. However, the mechanisms of fouling are complex because of the deformability and potential for coalescence and break-up of the oil droplets. Here, we report for the first time direct, three-dimensional (3D) visualization of oil droplets on electrospun fiber microfiltration membranes after a period of membrane-based separation of oil-in-water emulsions. High-resolution 3D images were acquired by a dual-channel confocal laser scanning microscopy (CLSM) technique in which both the fibers and the oil (dodecane) were fluorescently labeled. The morphology of dodecane as the foulant was observed for two different types of fibers, an oleophobic nylon (PA6(3)T), and oleophilic polyvinylidene fluoride (PVDF). Through direct visualization, the rejected oil was found to form droplets of clam-shell shape on the PA6(3)T fibers, whereas the oil tended to wet the PVDF fibers and spread across the membrane. The morphology was also analyzed as a function of separation time (i.e., "4D" imaging), as the oil accumulated within and upon the membranes. The observations are qualitatively consistent with a transition from blocking of individual pores in the membrane to coalescence of oil droplets into coherent liquid films with increasing filtration time. Analysis of permeate flux using blocking filtration models corroborate the transition of fouling modes indicated by the 3D images. This direct, 3D visualization CLSM technique is a powerful tool for characterizing the mechanisms of fouling in membranes used for liquid emulsion separations.
关键词： membrane fouling,3D imaging,oil emulsion,microfiltration,direct visualization
更新于2025-11-21 11:08:12
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A hybrid nanomaterial with NIR-induced heat and associated hydroxyl radical generation for synergistic tumor therapy
摘要： Although photothermal therapy (PTT) and photodynamic therapy (PDT) are widely commended for tumor treatment recently, they still suffer severe challenges due to the non-specificity of photothermal agents (PTAs)/photosensitizers (PSs) and hypoxic tumor microenvironment. Here, an oxygen independent biomimetic nanoplatform based on carbon sphere dotted with cerium oxide and coated by cell membrane (MCSCe) was designed and synthesized with good biocompatibility, homologous targeting ability, and improved photophysical activity. Notably, MCSCe could realize accumulation of hydrogen peroxide (H2O2) in tumor cells and hyperthermia under single laser (808 nm) irradiation, which were simultaneously utilized by itself to produce more toxic hydroxyl radical (·OH). Resultantly, the synergistic therapeutic effect against tumor cells was obtained under near infrared (NIR) laser irradiation.
关键词： cerium oxide,H2O2 self-accumulation,cell membrane,tumor therapy,carbon sphere
更新于2025-11-21 11:01:37
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Core-Shell Modeling of Light Scattering by Vesicles: Effect of Size, Contents, and Lamellarity
摘要： Having a fast, reliable method for characterizing vesicles is vital for their use as model cell membranes in biophysics, synthetic biology, and origins of life studies. Instead of the traditionally used Rayleigh-Gans-Debye approximation, we use an exact extended Lorenz-Mie solution for how core-shell particles scatter light to model vesicle turbidity. This approach enables accurate interpretations of simple turbidimetric measurements and is able to accurately model highly scattering vesicles, such as larger vesicles, those with multiple layers, and those with encapsulated material. We uncover several surprising features, including that vesicle lamellarity has a larger effect on sample turbidity than vesicle size and that the technique can be used to measure the membrane thickness of vesicles. We also examine potential misinterpretations of turbidimetry and discuss when measurements are limited by forward and multiple scattering and by the geometry of the instrument.
关键词： Lorenz-Mie theory,turbidimetry,membrane thickness,vesicles,lamellarity,light scattering
更新于2025-11-19 16:56:35
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Robust Janus fibrous membrane switchable infrared radiation properties for potential building thermal management application
摘要： Buildings heating and cooling consumes a large part of global energy, contributing to aggravating the global warming and energy crisis. It is strongly desired but still lacking in realizing heating and cooling functions within the same material without intensive energy input. Herein, a Janus thermal management membrane with trilayer structure has been prepared by using the ZnO nanorods array-coated cellulose (ZnO-NRs@cellulose), ultralong MnO2 nanowires (UL-MnO2-NWs) and silver nanowires (Ag-NWs) as building blocks. The ZnO-NRs@cellulose fiber layer with rough surface was fabricated by a hydrothermal progress based on the controlled growth of ZnO nanorods on cellulose surfaces. Subsequently, the hydrothermally synthesized UL-MnO2-NWs and Ag-NWs were filtered onto the ZnO-NRs@cellulose layer in turn, forming laminated Janus membrane. The Janus membrane exhibited asymmetric radiation properties on each side: the ZnO-NRs@cellulose side of the Janus membrane shows high solar radiation reflectivity and high infrared emissivity to minimize heat input from sun and enhance the heat dissipation in hot environment, while Ag-NWs side of that exhibits relatively high solar radiation absorption rate and low infrared emissivity for enhancing heat input from sun and reducing the heat radiation loss in cold environment. The introduction of UL-MnO2-NWs and Ag-NWs into the laminated Janus membrane endows the membrane with high tensile stress of 61.4 MPa. Moreover, the strong compatible entanglement among three layers of the Janus membrane causes the satisfactory interface stability. Due to the special asymmetric radiation performance, excellent interfacial compatibility, and high mechanical stability, such Janus membrane might be potential useful in building energy saving, personal thermal management and other facilities.
关键词： solar radiation,infrared radiation,laminated structure,MnO2 nanowire,Ag nanowire,Janus membrane
更新于2025-11-19 16:56:35
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Fluorescence coupled with chemometrics for simultaneous monitoring of cell concentration, cell viability and medium nitrate during production of carotenoid-rich Dunaliella salina
摘要： Two-dimensional (2D) ?uorescence spectroscopy was investigated as a monitoring tool for cultivation, harvesting, and e?uent treatment of Dunaliella salina with high carotenoid concentration; aiming to improve the production process and minimise costs. Chemometric analysis, namely Principal Component Analysis (PCA) and Projection to Latent Structures (PLS), were used to build models for estimation of cellular concentration, cellular viability, and nitrate concentration in media. The estimations were based on ?uorescence excitation-emission matrices (EEMs) acquired directly from algal suspensions. Cell concentration during cultivation and harvesting can be predicted by a single model capturing 92.0% of the variance, and with R2 of 0.92 and 0.97, for training and validation, respectively. Cell viability during harvesting by ultra?ltration was modelled with 79% of variance and R2 of 0.79 for training and 0.73 for validation. Nitrate concentration was successfully predicted during cultivation and permeate treatment using a single model with 81.8% of variance and R2 of 0.82 for training and 0.80 for validation. Therefore, this work demonstrates the strong potential of combining 2D ?uorescence and chemometrics for monitoring di?erent processes during microalgae production.
关键词： Membrane harvesting,Monitoring,Dunaliella salina,Carotenogenesis,Fluorescence EEMs
更新于2025-11-14 15:32:45
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Sexing of chicken eggs by fluorescence and Raman spectroscopy through the shell membrane
摘要： In order to provide an alternative to day-old chick culling in the layer hatcheries, a noninvasive method for egg sexing is required at an early stage of incubation before onset of embryo sensitivity. Fluorescence and Raman spectroscopy of blood offers the potential for precise and contactless in ovo sex determination of the domestic chicken (Gallus gallus f. dom.) eggs already during the fourth incubation day. However, such kind of optical spectroscopy requires a window in the egg shell, is thus invasive to the embryo and leads to decreased hatching rates. Here, we show that near infrared Raman and fluorescence spectroscopy can be performed on perfused extraembryonic vessels while leaving the inner egg shell membrane intact. Sparing the shell membrane makes the measurement minimally invasive, so that the sexing procedure does not affect hatching rates. We analyze the effect of the membrane above the vessels on fluorescence signal intensity and on Raman spectrum of blood, and propose a correction method to compensate for it. After compensation, we attain a correct sexing rate above 90% by applying supervised classification of spectra. Therefore, this approach offers the best premises towards practical deployment in the hatcheries.
关键词： Raman spectroscopy,sexing,chicken eggs,fluorescence spectroscopy,shell membrane
更新于2025-11-14 15:18:02
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Homo-molecular Fluorescence Complementation for Direct Visualization of Receptor Oligomerization in Living Cells
摘要： Cell surface receptor oligomerization is an attractive target process for drug screening. However, simple but reliable (thus high-throughput) visualization methods for receptor oligomerization are still lacking. Here, we report on a new single-construct Homo-molecular Fluorescence Complementation (Homo-FC) probe, which shows strong fluorescence signals by oligomerization of fused receptors in living cells with unexpectedly low background signals. Importantly, this high signal-to-noise ratio was not affected by expression level variations of fused receptors. The Homo-FC probe was developed by optimized flopped fusion of split fragments of superfolder green fluorescence protein and subsequent surface charge engineering. Homo-FC reliably visualized oligomerization of diverse natural receptors such as GPCR, EGFR, and even cytosolic DAI.
关键词： membrane receptor oligomerization,drug discovery,imaging,protein engineering,fluorescence complementation
更新于2025-09-23 15:23:52
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Effects of Protonation, Hydroxylamination, and Hydrazination of g-C3N4 on the Performance of Matrimid?/g-C3N4 Membranes
摘要： One of the challenges to continue improving polymeric membranes properties involves the development of novel chemically modified fillers, such as nitrogen-rich 2-D nanomaterials. Graphitic carbon nitride (g-C3N4) has attracted significant interest as a new class of these fillers. Protonation is known to afford it desirable functionalities to form unique architectures for various applications. In the work presented herein, doping of Matrimid? with protonated g-C3N4 to yield Matrimid?/g-C3N4 mixed matrix membranes was found to improve gas separation by enhancing the selectivity for CO2/CH4 by up to 36.9% at 0.5 wt % filler doping. With a view to further enhancing the contribution of g-C3N4 to the performance of the composite membrane, oxygen plasma and hydrazine monohydrate treatments were also assayed as alternatives to protonation. Hydroxylamination by oxygen plasma treatment increased the selectivity for CO2/CH4 by up to 52.2% (at 2 wt % doping) and that for O2/N2 by up to 26.3% (at 0.5 wt % doping). Hydrazination led to lower enhancements in CO2/CH4 separation, by up to 11.4%. This study suggests that chemically-modified g-C3N4 may hold promise as an additive for modifying the surface of Matrimid? and other membranes.
关键词： carbon nitride,O2/N2,Matrimid? 5218,CO2/CH4,gas separation,mixed matrix membrane
更新于2025-09-23 15:23:52