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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Characterization of Encapsulant Degradation in Accelerated UV Stressed Mini-Modules with UV-cut and UV-pass EVA
摘要： Automated cell segmentation for microscopy cell images has recently become an initial step for further image analysis in cell biology. However, microscopy cell images are easily degraded by noise during the readout procedure via optical-electronic imaging systems. Such noise degradations result in low signal-to-noise ratio (SNR) and poor image quality for cell identification. In order to improve SNR for subsequent segmentation and image-based quantitative analysis, the commonly used state-of-art restoration techniques are applied but few of them are suitable for corrupted microscopy cell images. In this paper, we propose a multistaged method based on a novel integration of trend surface analysis, quantile–quantile plot, bootstrapping, and the Gaussian spatial kernel for the restoration of noisy microscopy cell images. We show this multistaged approach achieves higher performance compared with other state-of-art restoration techniques in terms of peak signal-to-noise ratio and structure similarity in synthetic noise experiments. This paper also reports an experiment on real noisy microscopy data which demonstrated the advantages of the proposed restoration method for improving segmentation performance.
关键词： microscopy cell imaging,Bootstrapping,trend surface analysis,quantile–quantile plot (Q–Q) plot,Gaussian noise,image restoration
更新于2025-09-23 15:19:57
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Fluorescent-Nitrogen-Doped Carbon Quantum Dots Derived from Citrus Lemon Juice: Green Synthesis, Mercury(II) Ion Sensing, and Live Cell Imaging
摘要： In this study, we report a green and economical hydrothermal synthesis of fluorescent-nitrogen-doped carbon quantum dots (NCQDs) using citrus lemon as a carbon source. The prepared NCQDs possess high water solubility, high ionic stability, resistance to photobleaching, and bright blue color under ultraviolet radiation with a high quantum yield (～31%). High-resolution transmission electron microscopy (HRTEM) results show that the prepared NCQDs have a narrow size distribution (1?6 nm) with an average particle size of 3 nm. The mercury ion (Hg2+) sensing efficiency of the NCQDs was studied, and the result indicated that the material has high sensitivity, high precision, and good selectivity for Hg2+. The limit of detection (LOD) is 5.3 nM and the limit of quantification (LOQ) is 18.3 nM at a 99% confidence level. The cytotoxicity was evaluated using MCF7 cells, and the cell viabilities were determined to be greater than 88% upon the addition of NCQDs over a wide concentration range from 0 to 2 mg/mL. Based on the low cytotoxicity, good biocompatibility, and other revealed interesting merits, we also applied the prepared NCQDs as an effective fluorescent probe for multicolor live cell imaging.
关键词： mercury(II) ion sensing,citrus lemon juice,green synthesis,live cell imaging,fluorescent-nitrogen-doped carbon quantum dots
更新于2025-09-23 15:19:57
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Bridge between Temperature and Light: Bottom-Up Synthetic Route to Structure-Defined Graphene Quantum Dots as a Temperature Probe In Vitro and in Cells
摘要： Owing to their unique superiorities in chemical and photoluminescence (PL) stability, low toxicity, biocompatibility, and easy functionalization, graphene quantum dots (GQDs) were widely used in cell imaging, probes, and sensors. However, further development and deeper research of GQDs were restricted by their imprecise and complex structure and accompanying controversial PL mechanism. In this work, two kinds of structure defined water-soluble GQDs, with different oxidation degree, were synthesized from molecules by using bottom-up syntheses methods. After studied by a serial of characterizations, their optical properties, functional groups, molecular weight, and structural information were obtained. The optical properties of GQDs could be optimized by controlling their oxidation degree. PL mechanism of GQDs was investigated by comparing their structure and properties. Furthermore, robust, stable, and precise temperature probes were designed by using the GQDs, which exhibited an excellent wide responding range, which covered the whole physiology temperature range, from 0 ℃ to 60 ℃ in water. Moreover, the GQDs were successfully applied as temperature responsive fluorescence probe in Hela cell line. These works put forward a solid foundation for the applications of biological thermo probes and selectively temperature detectors in vitro cellular and in vivo.
关键词： structure controllable,living cell imaging,temperature probe,bottom-up synthesis,mechanism,graphene quantum dots
更新于2025-09-23 15:19:57
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Subcellular chemical imaging of structurally similar acridine drugs by near-field laser desorption/laser postionization mass spectrometry
摘要： Insights into the pharmacologic effect on cellular processes and the potential toxicological effects are vital to new drug development and evaluation, yet research on these subjects remains a great challenge due to the lack of information regarding the spatiotemporal distribution of drugs and metabolites within a single cell. Mass spectrometry imaging (MSI) has proven to be a label-free and high-throughput approach for visualizing drug distribution in spatial and temporal domains. However, single-cell drug imaging has been limited so far by detection sensitivity and microscale lateral resolution. Herein, we report near-field laser desorption/laser postionization mass spectrometry (NDPI-MS) for single-cell imaging of two structurally similar drugs, proflavine and ethacridine, and subcellular distributions of proflavine at different drug concentrations were investigated. The NDPI-MS imaging results indicate that proflavine was accumulated in lysosomes, which was verified by laser scanning confocal microscopy (LSCM). Additionally, a distinguished subcellular distribution pattern of ethacridine from proflavine could be visualized, highlighting the complexity of the interaction between the drugs and biological environment even though these two drugs possess similar structures. Taken together, the present results demonstrate the great potential of the integrated single-cell MSI platform for characterizing the drug distribution and its phenotype changes within individual cells, expediting the identification and evaluation of newly developed drugs.
关键词： single cell imaging,mass spectrometry,acridine drugs,laser postionization,near-field
更新于2025-09-23 15:19:57
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A highly selective “turn-on” fluorescent probe for detecting Cu2+ in two different sensing mechanisms
摘要： A new coumarin-derived hydrazone (1) has been developed as a “turn-on” fluorescent probe for the detection of Cu2+ in two different sensing mechanisms. In anhydrous acetonitrile, the strong fluorescence response of 1 to Cu2+ was mainly attributed to the chelation-controlled C=N isomerisation. Besides, S-donor is indispensable in protecting from the Cu2+-induced fluorescence quenching. In aqueous acetonitrile, 1 as a chemodosimeter can highly selectively sense of Cu2+, which was ascribed to the Cu2+-promoted cyclization reaction affording the strong fluorescent cyclization product (2). The proposed cyclization reaction was confirmed by the single-crystal structure of 2. Furthermore, 1 was utilized for imaging intracellular Cu2+ with good performance.
关键词： Live cell imaging,Fluorescent probe,Copper ion,Coumarin,Cyclization
更新于2025-09-23 15:19:57
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Selective Visualization of Live-Cell Mitochondrial Thiophenols and Their Induced Oxidative Stress Process by a Rationally Designed Rhodol-Based Fluorescent Probe
摘要： Mitochondria as cellular powerhouses are the preferential targets affected by thiophenols, an important class of highly toxic environmental pollutants, and are linked to the production of pathogenic reactive oxygen species (ROS) induced by trace thiophenol residues. For real-time and accurate sensing, it is critically important to develop highly sensitive fluorescent probes for the specific detection of mitochondrial thiophenols. Herein, we report the first mitochondria-targeted fluorescent probe (ROAL) to image thiophenols in living cells. The development of ROAL was based on a novel red-emitting rhodol derivative (ROAP). ROAL proved to be highly selective to thiophenols among various analytes including aliphatic thiols, and renders an ultrasensitive off-on fluorescence response to thiophenols with a remarkable detection limit (8.1 nM). The probe efficiently stains mitochondria with a high Pearson’s co-localization coefficient (0.95) using Mito Tracker Green FM as reference, thereby ensuring the specific detection of mitochondrial thiophenols in living HepG2 and HeLa cells. In particular, using this probe we for the first time proved that endogenous reactive oxygen species have the capacity to eliminate thiophenols in living cells, suggesting that thiophenols might induce cellular oxidative stress.
关键词： oxidative stress damage,fluorescent probe,live-cell imaging,thiophenol,mitochondria-targeted
更新于2025-09-23 15:19:57
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A coumarin-based dual optical probe for homocysteine with rapid response time, high sensitivity and selectivity
摘要： In this study, a new coumarin-based fluorescent and chromogenic dual channel probe (DC) was used for the selective detection of homocysteine (Hcy) over other amino acids, especially for cysteine (Cys) and glutathione (GSH). When Hcy is present in the solution, the remarkable fluorescence enhancement and obvious blue shift in UV–vis spectra can be observed. In addition, the color change from purple to yellow can be observed clearly by unaided eyes. This probe DC has fast response time, excellent sensitivity and selectivity to Hcy. A linear relationship exists between the ratio of emissions at 486 and 625 nm, and Hcy can be detected in a wide concentration range (0 to 200 μM). The signal-to-background ratio of fluorescence at 486 nm can reach 8.4, and the detection limit is calculated to be 3.5 μM. The response mechanism is proved to be the Michael addition reaction by Hcy. Preliminary results on cell imaging enable the practical application of Hcy tracing in living cells.
关键词： Sensor,Fluorescent probe,dual optical probe,Coumarin,Homocysteine,Cell imaging
更新于2025-09-23 15:19:57
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A long-wavelength-emitting fluorescent probe for simultaneous discrimination of H2S/Cys/GSH and its bio-imaging applications
摘要： A long-wavelength fluorescent probe NR-CY was developed for simultaneous identification of cysteine / glutathione and sulphide by combining the derivative of Nile red with 7-nitrobenzofurazan. The response of NR-CY to thiols is regulated by intramolecular charge transfer and photoinduced electron transfer mechanisms. For sulphide at 560 nm, cysteine at 475 nm and glutathione at 425 nm, different absorbance increases can be observed. NR-CY can detect cysteine at fluorescence emission 543 nm and distinguish sulphide from other analytes by kinetic experiments at 636 nm. The probe showed a rapid response to these thiols (cysteine was 90 s and sulphide was 30 s). In addition, NR-CY has been successfully applied to live MCF-7 cell imaging.
关键词： biothiols,Fluorescent probe,cell imaging,long-wavelength-emitting
更新于2025-09-23 15:19:57
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Small-Molecule Fluorescent Probes for Live-Cell Super-Resolution Microscopy
摘要： Super-resolution fluorescence microscopy is a powerful tool to visualize biomolecules and cellular structures at the nanometer scale. Employing these techniques in living cells has opened up the possibility to study dynamic processes with unprecedented spatial and temporal resolution. Different physical approaches to super-resolution microscopy have been introduced over the last years. A bottleneck to apply these approaches for live-cell imaging has become the availability of appropriate fluorescent probes that can be specifically attached to biomolecules. In this perspective, we discuss the role of small-molecule fluorescent probes for live-cell super-resolution microscopy and the challenges that need to be overcome for their generation. Recent trends in the development of labeling strategies are reviewed together with the required chemical and spectroscopic properties of the probes. Finally, selected examples of the use of small-molecule fluorescent probes in live-cell super-resolution microscopy are given.
关键词： Bioorthogonal chemistry,Super-resolution microscopy,Live-cell imaging,Fluorogenic probes,Protein labeling
更新于2025-09-23 15:19:57
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Detection of Metabolic Changes Induced via Drug Treatments in Live Cancer Cells and Tissue Using Raman Imaging Microscopy
摘要： Isocitrate dehydrogenase 1 (IDH1) mutations in gliomas, fibrosarcoma, and other cancers leads to a novel metabolite, D-2-hydroxyglutarate, which is proposed to cause tumorigenesis. The production of this metabolite also causes vulnerabilities in cellular metabolism, such as lowering NADPH levels. To exploit this vulnerability, we treated glioma and fibrosarcoma cells that harbor an IDH1 mutation with an inhibitor of nicotinamide adenine dinucleotide (NAD+) salvage pathway, FK866, and observed decreased viability in these cells. To understand the mechanism of action by which the inhibitor FK866 works, we used Raman imaging microscopy and identified that proteins and lipids are decreased upon treatment with the drug. Raman imaging showed a different distribution of lipids throughout the cell in the presence of the drug compared with the untreated cells. We employed nuclear magnetic resonance NMR spectroscopy and mass spectrometry to identify the classes of lipids altered. Our combined analyses point to a decrease in cell division due to loss of lipid content that contributes to membrane formation in the in vitro setting. However, the FK866 drug did not have the same potency in vivo. The use of Raman imaging microscopy indicated an opposite trend of lipid distribution in the tissue collected from treated versus untreated mice when compared with the cells. These results demonstrate the role of Raman imaging microscopy to identify and quantify metabolic changes in cancer cells and tissue.
关键词： NAD+ synthesis,tissue imaging,single cell imaging,microscopy,Raman spectrometry,fibrosarcoma IDH1
更新于2025-09-19 17:15:36