Статті в журналах: "Fluorescent analysis"

1

Nurgaziyeva, Elmira, Sarkyt Kudaibergenov, Grigoriy Mun, and Vitaliy Khutoryanskiy. "Synthesis of fluorescently-labelled poly(2-ethyl-2-oxazoline)-protected gold nanoparticles." Chemical Bulletin of Kazakh National University, no. 1 (March 19, 2021): 12–20. http://dx.doi.org/10.15328/cb1185.

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Gold nanoparticles (GNPs) protected by poly(2-ethyl-2-oxazoline) (POZ) of different molecular weights (Mw = 5, 50, 200 and 500 kDa) were synthesised and characterised by dynamic light scattering, nanoparticle tracking analysis, zeta potential measurement and transmission electron microscopy. It was established that the use of POZ with 50 kDa resulted in formation of GNPs with low polydispersity while POZ with greater molecular weights led to formation of more polydisperse GNPs. Fluorescent labelling of these nanoparticles was achieved through their reaction with polyethyleneglycol dithiol (8-12 kDa) as a linker molecule with subsequent reaction with 6-(iodoacetamido) fluorescein. The fluorescent nature of obtained GNPs was confirmed by the appearance of the fluorescence peak at 510 nm that is typical for fluorescein molecules and glowing of the aqueous solution under the UV irradiaton. The fluorescently-labelled GNPs are promising tool in biomedical application to monitor the biological systems using fluorescent microscopy.

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2

Kim, In Jung, Yongbin Xu, and Ki Hyun Nam. "Spectroscopic and Structural Analysis of Cu2+-Induced Fluorescence Quenching of ZsYellow." Biosensors 10, no. 3 (March 23, 2020): 29. http://dx.doi.org/10.3390/bios10030029.

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Fluorescent proteins exhibit fluorescence quenching by specific transition metals, suggesting their potential as fluorescent protein-based metal biosensors. Each fluorescent protein exhibits unique spectroscopic properties and mechanisms for fluorescence quenching by metals. Therefore, the metal-induced fluorescence quenching analysis of various new fluorescent proteins would be important step towards the development of such fluorescent protein-based metal biosensors. Here, we first report the spectroscopic and structural analysis of the yellow fluorescent protein ZsYellow, following its metal-induced quenching. Spectroscopic analysis showed that ZsYellow exhibited a high degree of fluorescence quenching by Cu2+. During Cu2+-induced ZsYellow quenching, fluorescence emission was recovered by adding EDTA. The crystal structure of ZsYellow soaked in Cu2+ solution was determined at a 2.6 Å resolution. The electron density map did not indicate the presence of Cu2+ around the chromophore or the β-barrel surface, which resulted in fluorescence quenching without Cu2+ binding to specific site in ZsYellow. Based on these results, we propose the fluorescence quenching to occur in a distance-dependent manner between the metal and the fluorescent protein, when these components get to a closer vicinity at higher metal concentrations. Our results provide useful insights for future development of fluorescent protein-based metal biosensors.

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3

Shao, Lei, Longyu Zhang, Shilin Li, and Pengyuan Zhang. "Design and Quantitative Analysis of Cancer Detection System Based on Fluorescence Immune Analysis." Journal of Healthcare Engineering 2019 (December 24, 2019): 1–9. http://dx.doi.org/10.1155/2019/1672940.

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Human blood is an important medical detection index. With the development in clinical medical detection instruments and detection technology, the requirements for detection accuracy and efficiency have been gradually improved. Fluorescent immunochromatography is a new detection technique. It has the characteristics of high efficiency, convenience, no pollution, and wide detection range. Human blood can be detected quickly using fluorescent immunochromatography. At present, it has received great attention from the field of clinical testing. In this paper, a set of fluorescent immunochromatographic analyzer has been designed. It is mainly based on the principle of fluorescence immunochromatography. A new method of signal analysis and system design for fluorescent immunochromatography analyzer is proposed. By using the improved threshold function denoising algorithm, the quantitative detection of fluorescent immunochromatographic strip is realized. The concentration of pathogenic factors (cancer cells) in human serum can be measured conveniently and accurately. The system integrates many peripheral modules, including fluorescence signal acquisition, fluorescence signal processing, quantitative curve fitting, and test results. In this paper, the quantitative detection experiments of the system are carried out in three aspects: linearity, repeatability, and sensitivity. The experimental results show that the linear correlation coefficient is up to 0.9976, and the limit of detection is up to 0.05 ng/ml. The requirements of the system are satisfied. The system performance is good, and the quantitative result is accurate. Therefore, the establishment of a fluorescence analysis system is of great significance.

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4

Chugunova, М. M. "Metrology of fluorescent analysis in Russia and abroad." Metrologiya, no. 4 (2020): 52–68. http://dx.doi.org/10.32446/0132-4713.2020-4-52-68.

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Article contains overview of Russian and foreign reference materials of fluorescent properties, and possibility of their metrology using. Principle of sensitivity analysis for fluorescent instruments based on scaled relative fluorescence units are discussed. Technical and metrological characteristics of developed and certified in The All-Russian Research Institute for Optical and Physical Measurements fluorescence gauges kit based on organic dyes with various concentration are given.

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5

Liu, Mingxian, Fenglin Tang, Zhengli Yang, Jing Xu, and Xiupei Yang. "Recent Progress on Gold-Nanocluster-Based Fluorescent Probe for Environmental Analysis and Biological Sensing." Journal of Analytical Methods in Chemistry 2019 (January 2, 2019): 1–10. http://dx.doi.org/10.1155/2019/1095148.

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Gold nanoclusters (AuNCs) are one of metal nanoclusters, which play a pivotal role in the recent advances in the research of fluorescent probes for their fluorescence effect. They are favored by most researchers due to their strong stability in fluorescence and adjustability in fluorescence wavelength when compared to traditional organic fluorescent dyes. In this review, we introduce various synthesis strategies of gold-nanocluster-based fluorescent probes and summarize their application for environmental analysis and biological sensing. The use of gold-nanocluster-based fluorescent probes for the analysis of heavy metals and inorganic and organic pollutants is covered in the environmental analysis while biological labeling, imaging, and detection are presented in biological sensing.

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6

Waterman-Storer, C. M., and W. C. Salmon. "Fluorescent Speckle Microscopy in Studies of Cytoskeletal Dynamics During Cell Motility." Microscopy and Microanalysis 7, S2 (August 2001): 6–7. http://dx.doi.org/10.1017/s1431927600026106.

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We have discovered a new method, Fluorescent Speckle Microscopy (FSM), for analyzing the dynamic movement and turnover of macromolecular protein assemblies, such as the cytoskeleton, in living cells (Waterman-Storer et al., 1998). FSM compliments or replaces the techniques of fluorescence recovery after photobleaching or photoactivation of fluorescence for measuring protein dynamics in vivo. For FSM, cells are microinjected with a very low fraction of fluorescently labeled subunits that co-assemble with unlabeled subunits to give a structure with a fluorescent speckled appearance in diffraction-limited wide-field or confocal digital fluorescence images. At low fractions of fluorescent subunits relative to unlabeled subunits, fluorescent speckles vary randomly in intensity according to the number of fluorescent subunits within a diffraction-limited region. in time-lapse FSM image series, movement of the fluorescent speckle pattern indicates translocation of structures, while changes in speckle intensity indicate subunit turnover. We have used FSM to study microtubule and actin behavior in interphase and mitotic cells. We use kymograph analysis to quantitate the movement of speckled structures (Fig 1) and are currently developing analysis procedures to quantify subunit turnover in structures.We have applied these methods to the study of microtubule and actin cytoskeletal dynamics in migrating vertebrate cells in culture. Interactions between the microtubule and actin cytoskeletons underlie fundamental cellular processes such as cytokinesis and cell locomotion, but are poorly understood.

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7

Prapatpong, Pornpan, Thanayu Techa-In, Wantaporn Padungpuak, Sawanya Buranaphalin, and Leena Suntornsuk. "HPLC-Fluorescent Analysis of Memantine: An Investigation on Fluorescent Derivative Formation." Journal of Chemistry 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/672183.

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Memantine is an N-methyl-D-aspartate receptor antagonist recommended for treatment of Alzheimer’s disease. Due to the lack of chromophores/fluorophores in memantine molecule, this work focuses on a novel procedure for memantine-fluorescent derivative formation enabling it to be monitored by a fluorescence detector. 4-(N-Chloroformylmethyl-N-methyl)amino-7-N,N-dimethylaminosulphonyl 2,1,3-benzoxadiazole (DBD-COCl) was chosen as a fluorescent probe since the carbonyl chloride of DBD-COCl could easily react with the amine on memantine to form the fluorescent derivative. The derivatization was achieved at 5 : 1 of DBD-COCl and memantine, at 60°C for 50 min. Structure elucidation from mass spectrometry and infrared spectroscopy spectra confirmed the amide bond of memantine-DBD-COCl. The derivative was stable up to 24 h and could be monitored by high performance liquid chromatography (HPLC) coupled with a fluorescence detector using a VertiSep GES C18 column, acetonitrile and water (80 : 20) as the mobile phase with a flow rate of 1 mL/min using the excitation and emission wavelengths at 430 and 520 nm, respectively. The derivative was eluted at 4.50 min and was separated from the DBD-COCl. Preliminary validation data reveals good linearity (r2≥0.99), repeatability (%RSD < 0.54) and accuracy (%Rbetween 94 and 119%) with a limit of detection of 0.79 μg/mL.

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8

Zhou, Kun, Jian Tian, Qiushi Zhang, Xiangxi Meng, Kun Yang, and Qiushi Ren. "Simulation and quantitative analysis of fluorescence intensity distribution based on the Monte Carlo method." Journal of Innovative Optical Health Sciences 08, no. 06 (October 27, 2015): 1550038. http://dx.doi.org/10.1142/s1793545815500388.

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The Monte Carlo method is a versatile simulation algorithm to model the propagation of photons inside the biological tissues. It has been applied to the reconstruction of the fluorescence molecular tomography (FMT). However, such method suffers from low computational efficiency, and the time consumption is not desirable. One way to solve this problem is to introduce a priori knowledge which will facilitate iterative convergence. We presented an in vivo simulation environment for fluorescence molecular tomography (ISEFMT) using the Monte Carlo method to simulate the photon distribution of fluorescent objects and their sectional view in any direction quantitatively. A series of simulation experiments were carried out on different phantoms each with two fluorescent volumes to investigate the relationship among fluorescence intensity distribution and the excitation photon number, the locations and sizes of the fluorescence volumes, and the anisotropy coefficient. A significant principle was discovered, that along the direction of the excitation light, the fluorescent volume near the excitation point will provide shelter effect so that the energy of the fluorescent volume farther away from the excitation point is relatively lower. Through quantitative analysis, it was discovered that both the photon energy distribution on every cross section and the fluorescence intensity distributed in the two volumes exhibit exponential relationships. The two maximum positions in this distribution correspond to the centers of fluorescent volumes. Finally, we also explored the effect of the phantom coefficients on the exponential rule, and found out that the exponential rule still exists, only the coefficient of the exponential rule changed. Such results can be utilized in locating the positions of multiple fluorescent volumes in complicated FMT reconstruction involving multiple fluorescent volumes. Thus, a priori knowledge can be generalized, which would accelerate the reconstruction of FMT and even other images.

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9

Zhang, Zhihong, Heping Zhu, and Huseyin Guler. "Quantitative Analysis and Correction of Temperature Effects on Fluorescent Tracer Concentration Measurement." Sustainability 12, no. 11 (June 2, 2020): 4501. http://dx.doi.org/10.3390/su12114501.

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To ensure an accurate evaluation of pesticide spray application efficiency and pesticide mixture uniformity, reliable and accurate measurements of fluorescence concentrations in spray solutions are critical. The objectives of this research were to examine the effects of solution temperature on measured concentrations of fluorescent tracers as the simulated pesticides and to develop models to correct the deviation of measurements caused by temperature variations. Fluorescent tracers (Brilliant Sulfaflavine (BSF), Eosin, Fluorescein sodium salt) were selected for tests with the solution temperatures ranging from 10.0 °C to 45.0 °C. The results showed that the measured concentrations of BSF decreased as the solution temperature increased, and the decrement rate was high at the beginning and then slowed down and tended to become constant. In contrast, the concentrations of Eosin decreased slowly at the beginning and then noticeably increased as temperatures increased. On the other hand, the concentrations of Fluorescein sodium salt had little variations with its solution temperature. To ensure the measurement accuracy, correction models were developed using the response surface methodology to numerically correct the measured concentration errors due to variations with the solution temperature. Corrected concentrations using the models agreed well with the actual concentrations, and the overall relative errors were reduced from 42.36% to 2.91% for BSF, 11.72% to 1.55% for Eosin, and 2.68% to 1.17% for Fluorescein sodium salt. Thus, this approach can be used to improve pesticide sprayer performances by accurately quantifying droplet deposits on target crops and off-target areas.

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10

Stojanov, Spase, Tina Vida Plavec, Julijana Kristl, Špela Zupančič, and Aleš Berlec. "Engineering of Vaginal Lactobacilli to Express Fluorescent Proteins Enables the Analysis of Their Mixture in Nanofibers." International Journal of Molecular Sciences 22, no. 24 (December 20, 2021): 13631. http://dx.doi.org/10.3390/ijms222413631.

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Lactobacilli are a promising natural tool against vaginal dysbiosis and infections. However, new local delivery systems and additional knowledge about their distribution and mechanism of action would contribute to the development of effective medicine. This will be facilitated by the introduction of the techniques for effective, inexpensive, and real-time tracking of these probiotics following their release. Here, we engineered three model vaginal lactobacilli (Lactobacillus crispatus ATCC 33820, Lactobacillus gasseri ATCC 33323, and Lactobacillus jensenii ATCC 25258) and a control Lactobacillus plantarum ATCC 8014 to express fluorescent proteins with different spectral properties, including infrared fluorescent protein (IRFP), green fluorescent protein (GFP), red fluorescent protein (mCherry), and blue fluorescent protein (mTagBFP2). The expression of these fluorescent proteins differed between the Lactobacillus species and enabled quantification and discrimination between lactobacilli, with the longer wavelength fluorescent proteins showing superior resolving power. Each Lactobacillus strain was labeled with an individual fluorescent protein and incorporated into poly (ethylene oxide) nanofibers using electrospinning, as confirmed by fluorescence and scanning electron microscopy. The lactobacilli retained their fluorescence in nanofibers, as well as after nanofiber dissolution. To summarize, vaginal lactobacilli were incorporated into electrospun nanofibers to provide a potential solid vaginal delivery system, and the fluorescent proteins were introduced to distinguish between them and allow their tracking in the future probiotic-delivery studies.

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11

Davic, Andrew, and Michael Cascio. "Development of a Microfluidic Platform for Trace Lipid Analysis." Metabolites 11, no. 3 (February 24, 2021): 130. http://dx.doi.org/10.3390/metabo11030130.

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The inherent trace quantity of primary fatty acid amides found in biological systems presents challenges for analytical analysis and quantitation, requiring a highly sensitive detection system. The use of microfluidics provides a green sample preparation and analysis technique through small-volume fluidic flow through micron-sized channels embedded in a polydimethylsiloxane (PDMS) device. Microfluidics provides the potential of having a micro total analysis system where chromatographic separation, fluorescent tagging reactions, and detection are accomplished with no added sample handling. This study describes the development and the optimization of a microfluidic-laser induced fluorescence (LIF) analysis and detection system that can be used for the detection of ultra-trace levels of fluorescently tagged primary fatty acid amines. A PDMS microfluidic device was designed and fabricated to incorporate droplet-based flow. Droplet microfluidics have enabled on-chip fluorescent tagging reactions to be performed quickly and efficiently, with no additional sample handling. An optimized LIF optical detection system provided fluorescently tagged primary fatty acid amine detection at sub-fmol levels (436 amol). The use of this LIF detection provides unparalleled sensitivity, with detection limits several orders of magnitude lower than currently employed LC-MS techniques, and might be easily adapted for use as a complementary quantification platform for parallel MS-based omics studies.

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12

Strohmeier, Karin, Martina Hofmann, Fabian Hauser, Dmitry Sivun, Sujitha Puthukodan, Andreas Karner, Georg Sandner, Pol-Edern Le Renard, Jaroslaw Jacak, and Mario Mairhofer. "CRISPR/Cas9 Genome Editing vs. Over-Expression for Fluorescent Extracellular Vesicle-Labeling: A Quantitative Analysis." International Journal of Molecular Sciences 23, no. 1 (December 28, 2021): 282. http://dx.doi.org/10.3390/ijms23010282.

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Over-expression of fluorescently-labeled markers for extracellular vesicles is frequently used to visualize vesicle up-take and transport. EVs that are labeled by over-expression show considerable heterogeneity regarding the number of fluorophores on single particles, which could potentially bias tracking and up-take studies in favor of more strongly-labeled particles. To avoid the potential artefacts that are caused by over-expression, we developed a genome editing approach for the fluorescent labeling of the extracellular vesicle marker CD63 with green fluorescent protein using the CRISPR/Cas9 technology. Using single-molecule sensitive fluorescence microscopy, we quantitatively compared the degree of labeling of secreted small extracellular vesicles from conventional over-expression and the CRISPR/Cas9 approach with true single-particle measurements. With our analysis, we can demonstrate a larger fraction of single-GFP-labeled EVs in the EVs that were isolated from CRISPR/Cas9-modified cells (83%) compared to EVs that were isolated from GFP-CD63 over-expressing cells (36%). Despite only single-GFP-labeling, CRISPR-EVs can be detected and discriminated from auto-fluorescence after their up-take into cells. To demonstrate the flexibility of the CRISPR/Cas9 genome editing method, we fluorescently labeled EVs using the HaloTag® with lipid membrane permeable dye, JaneliaFluor® 646, which allowed us to perform 3D-localization microscopy of single EVs taken up by the cultured cells.

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13

Ho Hur, Kwang, Bin Wu, Yan Chen, and Joachim Mueller. "Time-Shifted Fluorescence Cumulant Analysis in Fluorescent Fluctuation Spectroscopy." Biophysical Journal 102, no. 3 (January 2012): 402a. http://dx.doi.org/10.1016/j.bpj.2011.11.2197.

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14

Farrakhova, Dina, Igor Romanishkin, Yuliya Maklygina, Lina Bezdetnaya, and Victor Loschenov. "Analysis of Fluorescence Decay Kinetics of Indocyanine Green Monomers and Aggregates in Brain Tumor Model In Vivo." Nanomaterials 11, no. 12 (November 24, 2021): 3185. http://dx.doi.org/10.3390/nano11123185.

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Spectroscopic approach with fluorescence time resolution allows one to determine the state of a brain tumor and its microenvironment via changes in the fluorescent dye’s fluorescence lifetime. Indocyanine green (ICG) is an acknowledged infra-red fluorescent dye that self-assembles into stable aggregate forms (ICG NPs). ICG NPs aggregates have a tendency to accumulate in the tumor with a maximum accumulation at 24 h after systemic administration, enabling extended intraoperative diagnostic. Fluorescence lifetime analysis of ICG and ICG NPs demonstrates different values for ICG monomers and H-aggregates, indicating promising suitability for fluorescent diagnostics of brain tumors due to their affinity to tumor cells and stability in biological tissue.

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15

Liu, Guangyang, Xiaodong Huang, Lingyun Li, Xiaomin Xu, Yanguo Zhang, Jun Lv, and Donghui Xu. "Recent Advances and Perspectives of Molecularly Imprinted Polymer-Based Fluorescent Sensors in Food and Environment Analysis." Nanomaterials 9, no. 7 (July 18, 2019): 1030. http://dx.doi.org/10.3390/nano9071030.

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Molecular imprinting technology (MIT), also known as molecular template technology, is a new technology involving material chemistry, polymer chemistry, biochemistry, and other multi-disciplinary approaches. This technology is used to realize the unique recognition ability of three-dimensional crosslinked polymers, called the molecularly imprinted polymers (MIPs). MIPs demonstrate a wide range of applicability, good plasticity, stability, and high selectivity, and their internal recognition sites can be selectively combined with template molecules to achieve selective recognition. A molecularly imprinted fluorescence sensor (MIFs) incorporates fluorescent materials (fluorescein or fluorescent nanoparticles) into a molecularly imprinted polymer synthesis system and transforms the binding sites between target molecules and molecularly imprinted materials into readable fluorescence signals. This sensor demonstrates the advantages of high sensitivity and selectivity of fluorescence detection. Molecularly imprinted materials demonstrate considerable research significance and broad application prospects. They are a research hotspot in the field of food and environment safety sensing analysis. In this study, the progress in the construction and application of MIFs was reviewed with emphasis on the preparation principle, detection methods, and molecular recognition mechanism. The applications of MIFs in food and environment safety detection in recent years were summarized, and the research trends and development prospects of MIFs were discussed.

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Begoyan, V. V., Ł. J. Weseliński, S. Xia, J. Fedie, S. Kannan, A. Ferrier, S. Rao, and M. Tanasova. "Multicolor GLUT5-permeable fluorescent probes for fructose transport analysis." Chemical Communications 54, no. 31 (2018): 3855–58. http://dx.doi.org/10.1039/c7cc09809j.

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A set of coumarin-based fluorescent sugar conjugates – ManCous is reported. ManCous are specific for fructose transporter GLUT5 and cover a broad range of the fluorescence spectrum providing essential tools for the evaluation of fructose transport capacity in live cells.

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17

Okamoto, Kazuki, Teppei Ebina, Naoki Fujii, Kuniaki Konishi, Yu Sato, Tetsuhiko Kashima, Risako Nakano, et al. "Tb3+-doped fluorescent glass for biology." Science Advances 7, no. 2 (January 2021): eabd2529. http://dx.doi.org/10.1126/sciadv.abd2529.

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Optical investigation and manipulation constitute the core of biological experiments. Here, we introduce a new borosilicate glass material that contains the rare-earth ion terbium(III) (Tb3+), which emits green fluorescence upon blue light excitation, similar to green fluorescent protein (GFP), and thus is widely compatible with conventional biological research environments. Micropipettes made of Tb3+-doped glass allowed us to target GFP-labeled cells for single-cell electroporation, single-cell transcriptome analysis (Patch-seq), and patch-clamp recording under real-time fluorescence microscopic control. The glass also exhibited potent third harmonic generation upon infrared laser excitation and was usable for online optical targeting of fluorescently labeled neurons in the in vivo neocortex. Thus, Tb3+-doped glass simplifies many procedures in biological experiments.

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18

Quercioli, Valentina, Cristina Di Primio, Antonio Casini, Lubbertus C. F. Mulder, Lenard S. Vranckx, Doortje Borrenberghs, Rik Gijsbers, Zeger Debyser, and Anna Cereseto. "Comparative Analysis of HIV-1 and Murine Leukemia Virus Three-Dimensional Nuclear Distributions." Journal of Virology 90, no. 10 (March 9, 2016): 5205–9. http://dx.doi.org/10.1128/jvi.03188-15.

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Recent advances in fluorescence microscopy allow three-dimensional analysis of HIV-1 preintegration complexes in the nuclei of infected cells. To extend this investigation to gammaretroviruses, we engineered a fluorescent Moloney murine leukemia virus (MLV) system consisting of MLV-integrase fused to enhanced green fluorescent protein (MLV-IN-EGFP). A comparative analysis of lentiviral (HIV-1) and gammaretroviral (MLV) fluorescent complexes in the nuclei of infected cells revealed their different spatial distributions. This research tool has the potential to achieve new insight into the nuclear biology of these retroviruses.

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19

Wadsworth, P., and E. D. Salmon. "Analysis of the treadmilling model during metaphase of mitosis using fluorescence redistribution after photobleaching." Journal of Cell Biology 102, no. 3 (March 1, 1986): 1032–38. http://dx.doi.org/10.1083/jcb.102.3.1032.

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One recent hypothesis for the mechanism of chromosome movement during mitosis predicts that a continual, uniform, poleward flow or "treadmilling" of microtubules occurs within the half-spindle between the chromosomes and the poles during mitosis (Margolis, R. L., and L. Wilson, 1981, Nature (Lond.), 293:705-711). We have tested this treadmilling hypothesis using fluorescent analog cytochemistry and measurements of fluorescence redistribution after photobleaching to examine microtubule behavior during metaphase of mitosis. Mitotic BSC 1 mammalian tissue culture cells or newt lung epithelial cells were microinjected with brain tubulin labeled with 5-(4,6-dichlorotriazin-2-yl) amino fluorescein (DTAF) to provide a fluorescent tracer of the endogenous tubulin pool. Using a laser microbeam, fluorescence in the half-spindle was photobleached in either a narrow 1.6 micron wide bar pattern across the half-spingle or in a circular area of 2.8 or 4.5 micron diameter. Fluorescence recovery in the spindle fibers, measured using video microscopy or photometric techniques, occurs as bleached DTAF-tubulin subunits within the microtubules are exchanged for unbleached DTAF-tubulin in the cytosol by steady-state microtubule assembly-disassembly pathways. Recovery of 75% of the bleached fluorescence follows first-order kinetics and has an average half-time of 37 sec, at 31-33 degrees C. No translocation of the bleached bar region could be detected during fluorescence recovery, and the rate of recovery was independent of the size of the bleached spot. These results reveal that, for 75% of the half-spindle microtubules, FRAP does not occur by a synchronous treadmilling mechanism.

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Diaz, Roberto Jose, Roberto Rey Dios, Eyas M. Hattab, Kelly Burrell, Patricia Rakopoulos, Nesrin Sabha, Cynthia Hawkins, Gelareh Zadeh, James T. Rutka, and Aaron A. Cohen-Gadol. "Study of the biodistribution of fluorescein in glioma-infiltrated mouse brain and histopathological correlation of intraoperative findings in high-grade gliomas resected under fluorescein fluorescence guidance." Journal of Neurosurgery 122, no. 6 (June 2015): 1360–69. http://dx.doi.org/10.3171/2015.2.jns132507.

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OBJECT Intravenous fluorescein sodium has been used during resection of high-grade gliomas to help the surgeon visualize tumor margins. Several studies have reported improved rates of gross-total resection (GTR) using high doses of fluorescein sodium under white light. The recent introduction of a fluorescein-specific camera that allows for high-quality intraoperative imaging and use of very low dose fluorescein has drawn new attention to this fluorophore. However, the ability of fluorescein to specifically stain glioma cells is not yet well understood. METHODS The authors designed an in vitro model to assess fluorescein uptake in normal human astrocytes and U251 malignant glioma cells. An in vivo experiment was also subsequently designed to study fluorescein uptake by intracranial U87 malignant glioma xenografts in male nonobese diabetic/severe combined immunodeficient mice. A genetically induced mouse glioma model was used to adjust for the possible confounding effect of an inflammatory response in the xenograft model. To assess the intraoperative application of this technology, the authors prospectively enrolled 12 patients who underwent fluorescein-guided resection of their high-grade gliomas using low-dose intravenous fluorescein and a microscope-integrated fluorescence module. Intraoperative fluorescent and nonfluorescent specimens at the tumor margins were randomly analyzed for histopathological correlation. RESULTS The in vitro and in vivo models suggest that fluorescein demarcation of glioma-invaded brain is the result of distribution of fluorescein into the extracellular space, most likely as a result of an abnormal blood-brain barrier. Glioblastoma tumor cell–specific uptake of fluorescein was not observed, and tumor cells appeared to mostly exclude fluorescein. For the 12 patients who underwent resection of their high-grade gliomas, the histopathological analysis of the resected specimens at the tumor margin confirmed the intraoperative fluorescent findings. Fluorescein fluorescence was highly specific (up to 90.9%) while its sensitivity was 82.2%. False negatives occurred due to lack of fluorescence in areas of diffuse, low-density cellular infiltration. Margins of contrast enhancement based on intraoperative MRI–guided StealthStation neuronavigation correlated well with fluorescent tumor margins. GTR of the contrast-enhancing area as guided by the fluorescent signal was achieved in 100% of cases based on postoperative MRI. CONCLUSIONS Fluorescein sodium does not appear to selectively accumulate in astrocytoma cells but in extracellular tumor cell-rich locations, suggesting that fluorescein is a marker for areas of compromised blood-brain barrier within high-grade astrocytoma. Fluorescein fluorescence appears to correlate intraoperatively with the areas of MR enhancement, thus representing a practical tool to help the surgeon achieve GTR of the enhancing tumor regions.

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Aydinoglu, Sabriye, Andrea Pasti, Tarita Biver, and Benedetta Mennucci. "Auramine O interaction with DNA: a combined spectroscopic and TD-DFT analysis." Physical Chemistry Chemical Physics 21, no. 37 (2019): 20606–12. http://dx.doi.org/10.1039/c9cp03071a.

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22

Suzuki, Yoshio. "Development of Magnetic Nanobeads Modified by Artificial Fluorescent Peptides for the Highly Sensitive and Selective Analysis of Oxytocin." Sensors 20, no. 20 (October 21, 2020): 5956. http://dx.doi.org/10.3390/s20205956.

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We describe two novel fluorescent peptides (compounds 1 and 2) targeting oxytocin with a boron-dipyrromethenyl group as the fluorophore bound to an artificial peptide based on the oxytocin receptor, and their application for the analysis of oxytocin levels in human serum using nanometer-sized magnetic beads modified by fluorescent peptides (FMB-1 and FMB-2). Under the optimized experimental protocols, FMB-1 and FMB-2 emitted low levels of fluorescence but emitted much higher levels of fluorescence when associated with oxytocin. The detection limit of oxytocin by FMB-2 was 0.4 pM, which is approximately 37.5 times higher than that of conventional methods, such as ELISA. Using these fluorescent sensors, oxytocin was specifically detected over a wide linear range with high sensitivity, good reusability, stability, precision, and reproducibility. This fluorescent sensor-based detection system thus enabled the measurement of oxytocin levels in human serum, which has widespread applications for oxytocin assays across varied research fields.

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Bell, Peter, Luk H. Vandenberghe, Di Wu, Julie Johnston, Maria Limberis, and James M. Wilson. "A Comparative Analysis of Novel Fluorescent Proteins as Reporters for Gene Transfer Studies." Journal of Histochemistry & Cytochemistry 55, no. 9 (May 3, 2007): 931–39. http://dx.doi.org/10.1369/jhc.7a7180.2007.

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We evaluated novel fluorescent proteins (FPs) as reporters for gene transfer in animals and cells with the aim to develop more-sensitive assays for vector development and the optimization of gene transfer strategies in gene therapy. Adeno-associated virus serotype 5 vectors carrying an expression cassette with a chicken β-actin promoter encoding the green FPs ZsGreen1, AcGFP1, hMGFP (with and without intron), and EGFP and the red FPs DsRed2 and TurboRFP were administered to mice at identical doses for each organ to target liver, lung, and muscle. Despite the fact that all FPs were expressed from an identical vector backbone, the observed number of fluorescent cells and fluorescence intensities varied between, but was consistent within, each combination of a specific protein and organ. The highest number of fluorescent cells was observed in liver with EGFP and in lung with ZsGreen1 and EGFP. In muscle, AcGFP1 and ZsGreen1 produced the most-intense fluorescence in fibers. In contrast, in culture cells, ZsGreen1 showed substantially stronger fluorescence than all other proteins. Our data demonstrate that each FP has tissue-specific expression profiles that need to be taken into consideration when comparing the performance of vectors in different organs.

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24

Wang, Shiqi, Binglin Shen, Sheng Ren, Yihua Zhao, Silu Zhang, Junle Qu, and Liwei Liu. "Implementation and application of FRET–FLIM technology." Journal of Innovative Optical Health Sciences 12, no. 05 (September 2019): 1930010. http://dx.doi.org/10.1142/s1793545819300106.

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With the development of the new detection methods and the function of fluorescent molecule, researchers hope to further explore the internal mechanisms of organisms, monitor changes in the intracellular microenvironment, and dynamic processes of molecular interactions in cells. Fluorescence resonance energy transfer (FRET) describes the energy transfer process between donor fluorescent molecules and acceptor fluorescent molecules. It is an important means to detect protein–protein interactions and protein conformation changes in cells. Fluorescence lifetime imaging microscopy (FLIM) enables noninvasive measurement of the fluorescence lifetime of fluorescent particles in vivo. The FRET–FLIM technology, which is use FLIM to quantify and analyze FRET, enables real-time monitoring of dynamic changes of proteins in biological cells and analysis of protein interaction mechanisms. The distance between donor and acceptor and their respective fluorescent lifetime, which are of great importance for studying the mechanism of intracellular activity can be obtained by data analysis and algorithm fitting.

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25

Likhtenshtein, Gertz I. "Stilbene Molecular Probes as Potential Materials for Bioengineering: Real Time Analysis of Antioxidants and Nitric Oxide, Immunoassay in Solution and Biomembranes Fluidity." Advanced Materials Research 699 (May 2013): 718–23. http://dx.doi.org/10.4028/www.scientific.net/amr.699.718.

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A series of fluorescent methods of analysis and investigation of system based on the use of stilbenes and potentially important in biochemistry, biophysics, biotechnology, and biomedicine were proposed and developed. In these methods, two new types of stilbene molecular probes have been used: (i) fluorescent photochrome molecules and (ii) super molecules containing fluorescent and fluorescent quenching segments. These methods utilize the following photochemical and photophysical phenomena: the fluorescence and phosphorescence quenching, photochrome photoisomerization, and triplet–triplet and singlet–singlet energy transfer. The fluorescence properties of the new probes were intensively exploited as the basis of several methodologies that include a real-time analysis of nitric oxide, immunoassay in solution, investigation of molecular dynamics of biomembranes in a wide range characteristic times, and characterization of sensors for antibodies. These techniques may be adapted to fibro-optic sensoring.

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26

Birbach, Andreas, and Johannes Schmid. "Fluorescent proteins and fluorescence resonance energy transfer (FRET) as tools in signaling research." Thrombosis and Haemostasis 97, no. 03 (2007): 378–84. http://dx.doi.org/10.1160/th06-08-0472.

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SummaryThe advent of fluorescent proteins has revolutionized signaling research, shifting focus from biochemical assays to analysis of live cells, organized tissues and even entire organisms. Modern applications of fluorescent proteins go beyond their use as specific markers of cells or tissues, allowing the researcher to visualize intracellular translocations as well as biochemical reactions. In this mini-review, we summarize the properties of a variety of fluorescent proteins, their detection using fluorescence microscopy and flow analysis, as well as their basic and more advanced applications, including fluorescence resonance energy transfer (FRET) to study signaling dynamics.

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27

Maxfield, Frederick R. "Characterization of endocytosis in intact cells by quantitative fluorescence microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 234–35. http://dx.doi.org/10.1017/s0424820100085472.

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Endocytosis, the process by which extracellular macromolecules are taken into the cell is particularly amenable to quantitative analysis using fluorescence techniques. Fluorescently-labeled proteins and other macromolecules are taken up by cells via receptor-mediated endocytosis or fluid phase pinocytosis. Recently, fluorescent lipid probes have also been synthesized which label the endocytic pathway, allowing observation of lipid membrane traffic.Digital imaging allows the manipulation of images, background and autofluorescence subtractions, and fluorescence intensity measurements of individual endocytic compartments. Image intensification microscopy and digital image processing have been used extensively for studies of endocytosis, including the measurements of endosome pH, and the identification and quantitation of endocytic vesicle fusion. Recently, pathways taken by endocytosed fluorescent molecules have been followed using the confocal microscope, adding a powerful tool to investigate questions about endocytosis which were very difficult to study with conventional, full-field microscopy techniques.

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28

Qin, Qiu Yan, Yi Ping Qian, Zi Yu Wang, and Xiao Lin Fan. "Design and Synthesis of Fluorescent Betahistine Conjugates with Unique Imaging Property." Advanced Materials Research 557-559 (July 2012): 712–15. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.712.

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Labeling cardiovascular drugs probes with a fluorescent tag is an alternative method of measuring drugs activities and distributions in vivo, and further using of advanced tools to diagnose or detect cardiovascular diseases. Using this approach, a fluorescent probe (betahistine-Flu, 1) of Betahistine-based was synthesized and characterized by 1H NMR, 13C NMR and LC-MS, and its UV-Vis absorption spectral and fluorescence spectral, and fluorescence imaging in cell model were investigated. It was found that the fluorescent probe display strong green fluorescence, and have good optical effect in cell. This study reveals a good and interesting results of betahistine-directed fluorescent probe, and its may be a possible candidate for cardiovascular disease diagnosis and analysis in vivo.

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29

Robinson, N. H., J. D. Allan, J. A. Huffman, P. H. Kaye, V. E. Foot, and M. Gallagher. "Cluster analysis of WIBS single particle bioaerosol data." Atmospheric Measurement Techniques Discussions 5, no. 5 (September 7, 2012): 6387–422. http://dx.doi.org/10.5194/amtd-5-6387-2012.

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Abstract. Hierarchical agglomerative cluster analysis was performed on single-particle multi-spatial datasets comprising optical diameter, asymmetry and three different fluorescence measurements, gathered using two dual Waveband Integrated Bioaerosol Sensor (WIBS). The technique is demonstrated on measurements of various fluorescent and non-fluorescent polystyrene latex spheres (PSL) before being applied to two separate contemporaneous ambient WIBS datasets recorded in a forest site in Colorado, USA as part of the BEACHON-RoMBAS project. Cluster analysis results between both datasets are consistent. Clusters are tentatively interpreted by comparison of concentration time series and cluster average measurement values to the published literature (of which there is a paucity) to represent: non-fluorescent accumulation mode aerosol; bacterial agglomerates; and fungal spores. To our knowledge, this is the first time cluster analysis has been applied to long term online PBAP measurements. The novel application of this clustering technique provides a means for routinely reducing WIBS data to discrete concentration time series which are more easily interpretable, without the need for any a priori assumptions concerning the expected aerosol types. It can reduce the level of subjectivity compared to the more standard analysis approaches, which are typically performed by simple inspection of various ensemble data products. It also has the advantage of potentially resolving less populous or subtly different particle types. This technique is likely to become more robust in the future as fluorescence-based aerosol instrumentation measurement precision, dynamic range and the number of available metrics is improved.

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30

Murphy, Robert F., and Michael V. Boland. "Pattern Analysis Meets Cell Biology." Microscopy and Microanalysis 5, S2 (August 1999): 510–11. http://dx.doi.org/10.1017/s1431927600015877.

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The widespread availability of automated fluorescence microscope systems has led to an explosion in the acquisition of digital images by biologists. This has created a need for computer applications that automate the analysis of these images and an opportunity to develop new approaches to classical problems. An example is the determination of the subcellular location of a protein from immunofluorescence images (or, more recently, images of GFP fluorescence). Current practice is to compare such images to mental images that a cell biologist has developed over time, and to reach a tentative conclusion about the structure (i.e., organelle) that a protein is found in. Since this determination is subjective, it often must be followed up by double labeling with a marker protein from the suspected structure.As an initial exploration of the feasibility of automating the determination of subcellular location, we developed a system that is able to classify the localization patterns characteristic of five cellular molecules (proteins and DNA) in Chinese Hamster Ovary (CHO) cells. Images were acquired on an epifluorescence microscope after the cells had been fixed, permeabilized, and labeled with appropriate fluorescent reagents (usually antibodies conjugated to fluorescent dyes). The labels used were directed against a Golgi protein, a lysosomal protein, a nuclear protein, a cytoskeletal protein, and DNA.

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31

Frénoy, J. P., F. Emmanuel, and J. M. Salmon. "Use of quantitative image microfluorometry to follow fluorescent ricin internalization in single living cells." Journal of Histochemistry & Cytochemistry 42, no. 5 (May 1994): 627–33. http://dx.doi.org/10.1177/42.5.8157934.

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We used microspectrofluorometry and videomicrofluorometry to follow the binding and internalization of fluorescein-labeled toxic lectin ricin in living Zajdela hepatoma cells. Microspectrofluorometry showed that when ricin was specifically labeled on its B-chain with one molecule of fluorescein (ABF), its fluorescence spectrum did not alter during its binding to the cell surface and subsequent internalization. This enabled us to use image analysis to follow cell internalization of labeled ricin. Accordingly, we measured the appropriate fluorescent cell parameters, comprising total fluorescence intensity, cell surface area, mean fluorescence intensity and its standard error, and used the measurements for mono- and biparametric studies of cell fluorescence distribution. The results showed that (a) ricin binds two different subpopulations of Zajdela hepatoma cells, (b) Zajdela hepatoma cells internalize ricin rapidly and after a relatively stable period of 1-2 hr, internalization starts again at 4 hr, and (c) the distribution of intracellular fluorescence is heterogeneous and ABF accumulates in certain cellular localizations. Our results demonstrate that quantitative microfluorometry is an effective and interesting approach for real-time studies of macromolecule internalization in living cells.

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32

Burghardt, Robert C., and Rola Barhoumi. "Analysis of Mechanisms of Cellular Injury on the Micrometer Scale." Microscopy and Microanalysis 3, S2 (August 1997): 37–38. http://dx.doi.org/10.1017/s1431927600007078.

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Non-invasive imaging tools using biosensors and biomarkers for defining the function of living cells and tissues are among rapidly emerging technologies being developed to monitor cellular toxicity mechanisms. Commercially available fluorescence probes and naturally occurring fluorescent molecules can be used to quantitatively monitor a number of functional endpoints in cultured cells. Innovative approaches to exploit the sensitivity, spectroscopy and temporal/spatial resolution properties of fluorescent probes may provide sensitive approaches for analysis of the molecular mechanisms of toxicity in cells exposed to a variety of toxicants. Kinetic analysis of multiple cellular parameters such as intracellular glutathione (GSH) and Ca2+ content, reactive oxygen species (ROS) generation, mitochondrial and plasma membrane potentials, intracellular pH, and gap junction-mediated intercellular communication (GJIC) with cellular component-specific fluorescent probes permits rapid identification of changes in these parameters and the chronology of injury in cells caused by acute toxicant exposure. Cellular signal transduction mechanisms are also likely to be vulnerable to toxic insults.

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33

Giordani, Silvia, Juergen Bartelmess, Marco Frasconi, Ilaria Biondi, Shane Cheung, Marco Grossi, Dan Wu, Luis Echegoyen, and Donal F. O'Shea. "NIR fluorescence labelled carbon nano-onions: synthesis, analysis and cellular imaging." J. Mater. Chem. B 2, no. 42 (2014): 7459–63. http://dx.doi.org/10.1039/c4tb01087f.

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The synthesis and characterisation of carbon nano-onion materials functionalised with NIR fluorescent boron difluoride azadipyrromethenes is described. They reveal reversible NIR fluorescence on-off-switching in response to pH changes both in solution and intracellularly.

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34

Beal, Jacob, Geoff S. Baldwin, Natalie G. Farny, Markus Gershater, Traci Haddock-Angelli, Russell Buckley-Taylor, Ari Dwijayanti, et al. "Comparative analysis of three studies measuring fluorescence from engineered bacterial genetic constructs." PLOS ONE 16, no. 6 (June 7, 2021): e0252263. http://dx.doi.org/10.1371/journal.pone.0252263.

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Reproducibility is a key challenge of synthetic biology, but the foundation of reproducibility is only as solid as the reference materials it is built upon. Here we focus on the reproducibility of fluorescence measurements from bacteria transformed with engineered genetic constructs. This comparative analysis comprises three large interlaboratory studies using flow cytometry and plate readers, identical genetic constructs, and compatible unit calibration protocols. Across all three studies, we find similarly high precision in the calibrants used for plate readers. We also find that fluorescence measurements agree closely across the flow cytometry results and two years of plate reader results, with an average standard deviation of 1.52-fold, while the third year of plate reader results are consistently shifted by more than an order of magnitude, with an average shift of 28.9-fold. Analyzing possible sources of error indicates this shift is due to incorrect preparation of the fluorescein calibrant. These findings suggest that measuring fluorescence from engineered constructs is highly reproducible, but also that there is a critical need for access to quality controlled fluorescent calibrants for plate readers.

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35

Huang Yuancheng, 黄远程, 张良培 Zhang Liangpei, 李平湘 Li Pingxiang, and 钟燕飞 Zhong Yanfei. "Pure Spectral Analysis and Fluorescent Signal Separation for Multispectral Fluorescence Imaging." Acta Optica Sinica 30, no. 12 (2010): 3631–36. http://dx.doi.org/10.3788/aos20103012.3631.

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36

Wang, Jian, Yonghui Song, Feng Qian, Cong Du, Huibin Yu, and Liancheng Xiang. "Removal Characteristics of Effluent Organic Matter (EfOM) in Pharmaceutical Tailwater by a Combined Coagulation and UV/O3 Process." Water 12, no. 10 (October 5, 2020): 2773. http://dx.doi.org/10.3390/w12102773.

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A novel coagulation combined with UV/O3 process was employed to remove the effluent organic matter (EfOM) from a biotreated pharmaceutical wastewater for harmlessness. The removal behavior of EfOM by UV/O3 process was characterized by synchronous fluorescence spectroscopy (SFS) integrating two-dimensional correlation (2D-COS) and principal component analysis (PCA) technology. The highest dissolved organic carbon (DOC) and ratio of UV254 and DOC (SUVA) removal efficiency reached 55.8% and 68.7% by coagulation-UV/O3 process after 60 min oxidation, respectively. Five main components of pharmaceutical tail wastewater (PTW) were identified by SFS. Spectral analysis revealed that UV/O3 was selective for the removal of different fluorescent components, especially fulvic acid-like fluorescent (FLF) component and humus-like fluorescent (HLF) component. Synchronous fluorescence/UV-visible two-dimensional correlation spectra analysis showed that the degradation of organic matter occurred sequentially in the order of HLF, FLF, microbial humus-like fluorescence component (MHLF), tryptophan-like fluorescent component (TRLF), tyrosine-like fluorescent component (TYLF). The UV/O3 process removed 95.6% of HLF, 80.0% of FLF, 56.0% of TRLF, 50.8% of MHLF and 44.4% of TYLF. Therefore, the coagulation-UV/O3 process was proven to be an attractive way to reduce the environmental risks of PTW.

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37

Ning, Bo, Jun-Wen Cao, Xiao-Teng Zhou, He Qin, Ling-Xiao Li, and Cheng-You Kan. "Synthesis and characterization of a novel, reactive, yellow fluorescent organosilicon dye and its polysiloxanes." Journal of Chemical Research 43, no. 11-12 (August 30, 2019): 461–68. http://dx.doi.org/10.1177/1747519819872098.

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A novel, reactive, yellow fluorescent organosilicon dye, N-propyl-(diethoxy)methyl-silane-4-dimethylamino-naphthalimide, is designed and synthesized and is used to fabricate a covalently yellow fluorescent silicone oil by polycondensation of hydroxy-terminated polydimethylsiloxane. The chemical structure and optical properties of the N-propyl-(diethoxy)methyl-silane-4-dimethylamino-naphthalimide and covalently yellow fluorescent silicone oil are characterized by 1H nuclear magnetic resonance, 13C nuclear magnetic resonance, mass spectrometry, Fourier transform infrared, UV–Vis, and fluorescence spectra. The results indicate that the fluorescence quantum yields of N-propyl-(diethoxy)methyl-silane-4-dimethylamino-naphthalimide and covalently yellow fluorescent silicone oil are 2.61% and 3.5%, respectively. The λmax values of their dichloromethane solutions are 416 nm, and their λex and λem are 430 and 509 nm, respectively. Furthermore, covalently yellow fluorescent silicone rubbers are prepared using tetraethoxysilane as a cross-linker, and some of their properties are investigated. Thermogravimetric analysis and dynamic mechanical analysis show that heat resistance and tan δ of the covalently yellow fluorescent silicone rubber are improved in comparison with silicone rubbers without N-propyl-(diethoxy)methyl-silane-4-dimethylamino-naphthalimide moieties. Solvent extraction experiments indicate that the solvent resistance of the covalently yellow fluorescent silicone rubber is much better than that of noncovalently yellow fluorescent silicone rubber.

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38

Robinson, N. H., J. D. Allan, J. A. Huffman, P. H. Kaye, V. E. Foot, and M. Gallagher. "Cluster analysis of WIBS single-particle bioaerosol data." Atmospheric Measurement Techniques 6, no. 2 (February 13, 2013): 337–47. http://dx.doi.org/10.5194/amt-6-337-2013.

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Abstract. Hierarchical agglomerative cluster analysis was performed on single-particle multi-spatial data sets comprising optical diameter, asymmetry and three different fluorescence measurements, gathered using two dual Wideband Integrated Bioaerosol Sensors (WIBSs). The technique is demonstrated on measurements of various fluorescent and non-fluorescent polystyrene latex spheres (PSL) before being applied to two separate contemporaneous ambient WIBS data sets recorded in a forest site in Colorado, USA, as part of the BEACHON-RoMBAS project. Cluster analysis results between both data sets are consistent. Clusters are tentatively interpreted by comparison of concentration time series and cluster average measurement values to the published literature (of which there is a paucity) to represent the following: non-fluorescent accumulation mode aerosol; bacterial agglomerates; and fungal spores. To our knowledge, this is the first time cluster analysis has been applied to long-term online primary biological aerosol particle (PBAP) measurements. The novel application of this clustering technique provides a means for routinely reducing WIBS data to discrete concentration time series which are more easily interpretable, without the need for any a priori assumptions concerning the expected aerosol types. It can reduce the level of subjectivity compared to the more standard analysis approaches, which are typically performed by simple inspection of various ensemble data products. It also has the advantage of potentially resolving less populous or subtly different particle types. This technique is likely to become more robust in the future as fluorescence-based aerosol instrumentation measurement precision, dynamic range and the number of available metrics are improved.

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39

Goldsworthy, M., E. Tinkler-Hundal, T. Maisey, N. Corrigan, N. West, G. Gossedge, H. Andrew, G. Taylor, and D. Jayne. "5-Aminolevulinic acid-mediated fluorescence in colon cancer surgery: a histopathological analysis of fluorescent and non-fluorescent tumours." European Journal of Cancer 72 (February 2017): S61. http://dx.doi.org/10.1016/s0959-8049(17)30279-4.

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40

Tsai, Hweiyan, Kaiying Chang, Wanshing Lee, and C. Bor Fuh. "Rapid Preparation of Fluorescent Carbon Dots from Pine Needles for Chemical Analysis." Nanomaterials 12, no. 1 (December 28, 2021): 66. http://dx.doi.org/10.3390/nano12010066.

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Анотація:

Fluorescent carbon dots with blue, green, and red emissions were rapidly prepared from modified pine needles through microwave irradiation in a one-pot reaction. The fluorescence intensity and emission versatility for a carbon source were experimentally optimized. The reaction times were under 10 min and the reaction temperatures were lower than 220 °C. Potential applications of magnetic fluorescence-linked immunoassays of carcinoembryonic antigen (CEA) and tumor necrosis factor-alpha (TNF-α) were presented. The detection limits for CEA and TNF-α (3.1 and 2.8 pg mL−1, respectively) are lower than those presented in other reports, whereas the linear ranges for CEA and TNF-α (9 pg mL−1 to 18 ng mL−1 and 8.5 pg mL−1 to 17 ng mL−1, respectively) are wider than those presented in other reports. Magnetic immunoassays with fluorescent CDs prepared from pine needles can enable rapid, sensitive, and selective detections for biochemical analysis.

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41

Varga, Viktor Sebestyén, József Bocsi, Ferenc Sipos, Gábor Csendes, Zsolt Tulassay, and Béla Molnár. "Scanning fluorescent microscopy is an alternative for quantitative fluorescent cell analysis." Cytometry Part A 60A, no. 1 (June 9, 2004): 53–62. http://dx.doi.org/10.1002/cyto.a.20027.

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42

Fernandes, Gregory E., Ya-Wen Chang, Akash Sharma, and Sarah Tutt. "One-Step Assembly of Fluorescence-Based Cyanide Sensors from Inexpensive, Off-The-Shelf Materials." Sensors 20, no. 16 (August 11, 2020): 4488. http://dx.doi.org/10.3390/s20164488.

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We report a simple and versatile approach to assemble sensitive and selective fluorescence “turn-on” sensors for cyanide by combining three off-the-shelf materials; namely fluorescent dye, 1-vinyl imidazole polymer, and cupric chloride. The cyanide-sensing species is a non-fluorescent fluorophore-polymer-Cu2+ complex; which forms as a result of the imidazole polymer’s ability to bind both fluorophore and fluorescence quencher (Cu2+). Cyanide removes Cu2+ from these complexes; thereby “turning-on” sensor fluorescence. These sensors are water-soluble and have a detection limit of ~2.5 μM (CN−) in water. Our ternary complex-based sensing approach also enables facile emission tuning; we demonstrate the convenient, synthesis-free preparation of blue and green-emitting sensors using distyrylbiphenyl and fluorescein fluorophores, respectively. Furthermore; these ternary complexes are easily immobilized using agarose to create cyanide-sensing hydrogels; which are then used in a simple; novel microdiffusion apparatus to achieve interference-free cyanide analysis of aqueous media. The present study provides an inexpensive approach for portable; interference-free cyanide detection.

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43

Asieieva, Dasha. "METHODS OF SYNTHESIS AND FEATURES OF USING SYSTEMS BASED ON MORIN-METAL COMPLEXES IN FLUORESCENT ANALYSIS METHODS." Ukrainian Chemistry Journal 87, no. 10 (November 26, 2021): 74–89. http://dx.doi.org/10.33609/2708-129x.87.10.2021.74-89.

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Анотація:

The review describes modern physicochemical systems based on complex compounds with organic ligands, which may have fluorescent properties when interacting with metal ions or proteins. Modern methods of synthesis of these compounds and their use in physical-chemical methods of analysis are given. Approaches to detecting the content of metals and proteins using the fluorescent properties of morin complex compounds are considered. Areas of use of the effects of amplification and quenching of fluorescence for the determination of organic compounds and metal ions, especially in the presence of DNA and RNA of different biological origin are described. The influence of surfactants on the fluorescence intensity of complexes with morin was analyzed separately.

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44

Russo, S. A., and O. Greengard. "gamma-Glutamyltranspeptidase activity in intact leukocytes: flow cytometric analysis and sorting." Journal of Histochemistry & Cytochemistry 37, no. 3 (March 1989): 323–30. http://dx.doi.org/10.1177/37.3.2563747.

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A fluorescent method developed for visualizing gamma-glutamyltranspeptidase (GGT) in intact liver cells was adapted to leukocytes and used in a multiparameter flow cytometric study of blood and bone marrow cells from rats with subcutaneous implants of mammary carcinoma 5A. The severe granulocytosis caused by this non-metastatic tumor was preceded by a progressive rise in the percentage of leukocytes with high GGT fluorescence. Both granulocytes and small, immature cells of bone marrow showed increased GGT expression, whereas in blood this increase was attributable entirely to mature granulocytes. At 28 days (but not yet at 14 days) after carcinoma implantation, 20-30% of blood or bone marrow granulocytes constituted a distinct subpopulation in that their GGT fluorescence intensity range was much higher and did not overlap with the range for the rest of the population. The results indicate that fluorescent GGT assay of intact leukocytes provides a useful probe for flow cytometric analysis of population heterogeneity in leukoproliferative disorders.

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45

Aldave, Guillermo, Sonia Tejada, Eva Pay, Miguel Marigil, Bartolomé Bejarano, Miguel A. Idoate, and Ricardo Díez-Valle. "Prognostic Value of Residual Fluorescent Tissue in Glioblastoma Patients After Gross Total Resection in 5-Aminolevulinic Acid-Guided Surgery." Neurosurgery 72, no. 6 (February 19, 2013): 915–21. http://dx.doi.org/10.1227/neu.0b013e31828c3974.

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Abstract BACKGROUND: There is evidence in the literature supporting that fluorescent tissue signal in fluorescence-guided surgery extends farther than tissue highlighted in gadolinium in T1 sequence magnetic resonance imaging (MRI), which is the standard to quantify the extent of resection. OBJECTIVE: To study whether the presence of residual fluorescent tissue after surgery carries a different prognosis for glioblastoma (GBM) cases with complete resection confirmed by MRI. METHODS: A retrospective review in our center found 118 consecutive patients with high-grade gliomas operated on with the use of fluorescence-guided surgery with 5-aminolevulinic acid. Within that series, the 52 patients with newly diagnosed GBM and complete resection of enhancing tumor (CRET) in early MRI were selected for analysis. We studied the influence of residual fluorescence in the surgical field on overall survival and neurological complication rate. Multivariate analysis included potential relevant factors: age, Karnofsky Performance Scale, O6-methylguanine methyltransferase methylation promoter status, tumor eloquent location, preoperative tumor volume, and adjuvant therapy. RESULTS: The median overall survival was 27.0 months (confidence interval = 22.4-31.6) in patients with nonresidual fluorescence (n = 25) and 17.5 months (confidence interval = 12.5-22.5) for the group with residual fluorescence (n = 27) (P = .015). The influence of residual fluorescence was maintained in the multivariate analysis with all covariables, hazard ratio = 2.5 (P = .041). The neurological complication rate was 18.5% in patients with nonresidual fluorescence and 8% for the group with residual fluorescence (P = .267). CONCLUSION: GBM patients with CRET in early MRI and no fluorescent residual tissue had longer overall survival than patients with CRET and residual fluorescent tissue.

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46

Jin, Xin, Xin Liu, Xiaohua Zhu, Hao Li, Wang Li, Yan Huang, and Shouzhuo Yao. "A label-free fluorescence assay for thrombin activity analysis based on fluorescent protein and gold nanoparticles." Analytical Methods 8, no. 18 (2016): 3691–97. http://dx.doi.org/10.1039/c6ay00290k.

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Анотація:

A label-free and sensitive fluorescence assay has been developed for probing thrombin activity based on an engineered enhanced green fluorescent protein (EGFP) probe and unmodified gold nanoparticles (AuNPs).

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47

Hofgaard, Johannes P., Sarah Mollerup, Niels-Henrik Holstein-Rathlou, and Morten Schak Nielsen. "Quantification of gap junctional intercellular communication based on digital image analysis." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 297, no. 2 (August 2009): R243—R247. http://dx.doi.org/10.1152/ajpregu.00089.2009.

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Intercellular communication via gap junction channels can be quantified by several methods based on diffusion of fluorescent dyes or metabolites. Given the variation in intercellular coupling of cells, even under untreated control conditions, it is of essence to quantify the coupling between numerous cells to obtain reliable estimates of metabolic coupling. Quantification is often based on manual counting of fluorescent cells, which is time consuming and may include some degree of subjectivity. In this report, we introduce a technique based on digital image analysis, and the software for the analysis is presented together with a detailed protocol in the online supplemental material ( http://bmi.ku.dk/matlab_program/ ). Fluorescent dye was introduced in connexin 43-expressing C6 glioma cells by in situ electroporation, and fluorescence intensity was measured in the electroporated cells and in cells receiving dye by intercellular diffusion. The analysis performed is semiautomatic, and comparison with traditional cell counting shows that this method reliably determines the effect of uncoupling by several interventions. This new method of analysis yields a rapid and objective quantification process with a high degree of reproducibility.

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48

Yuan, Fang, Huimin Zhao, Zhinan Zhang, Lichen Gao, Jintao Xu, and Xie Quan. "Fluorescent biosensor for sensitive analysis of oxytetracycline based on an indirectly labelled long-chain aptamer." RSC Advances 5, no. 72 (2015): 58895–901. http://dx.doi.org/10.1039/c5ra04025f.

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Анотація:

A fluorescent assay for oxytetracycline detection is presented based on an indirectly fluorescein-labelled aptamer probe, which was fabricated through hybridization of an oxytetracycline long-chain aptamer with a FAM-labelled short-chain ssDNA.

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49

Le, X. Chris, Victor Pavski, and Hailin Wang. "2002 W.A.E. McBryde Award Lecture Affinity recognition, capillary electrophoresis, and laser-induced fluorescence polarization for ultrasensitive bioanalysis." Canadian Journal of Chemistry 83, no. 3 (March 1, 2005): 185–94. http://dx.doi.org/10.1139/v04-175.

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The combination of affinity recognition, capillary electrophoresis (CE), laser-induced fluorescence (LIF), and fluorescence polarization for the ultrasensitive determination of compounds of biological interest is described. Competitive immunoassays using CELIF eliminate the need for fluorescently labeling trace analytes of interest and are particularly useful for determination of small molecules, such as cyclosporine, gentamicin, vancomycin, and digoxin. Fluorescence polarization allows for differentiation of the antibody-bound from the unbound small molecules. Noncompetitive affinity CELIF assays are shown to be highly effective in the determination of biomarkers for DNA damage and HIV-1 infection. An antibody (or aptamer) is used as a fluorescent probe to bind with a target DNA adduct (or the reverse transcriptase of the HIV-1 virus), with the fluorescent reaction products being separated by CE and detected by LIF. Aptamers are attractive affinity probes for protein analysis because of high affinity, high specificity, and the potential for a wide range of target proteins. Fluorescence polarization provides unique information for studying molecular interactions. Innovative integrations of these technologies will have broad applications ranging from cancer research, to biomedical diagnosis, to pharmaceutical and environmental analyses.Key words: capillary electrophoresis, laser-induced fluorescence, fluorescence polarization, immunoassay, affinity probes, antibodies, aptamers, DNA damage, toxins, therapeutic drugs.

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50

Gupta, Anjali, Thomas Korte, Andreas Herrmann, and Thorsten Wohland. "Plasma membrane asymmetry of lipid organization: fluorescence lifetime microscopy and correlation spectroscopy analysis." Journal of Lipid Research 61, no. 2 (December 19, 2019): 252–66. http://dx.doi.org/10.1194/jlr.d119000364.

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A fundamental feature of the eukaryotic cell membrane is the asymmetric arrangement of lipids in its two leaflets. A cell invests significant energy to maintain this asymmetry and uses it to regulate important biological processes, such as apoptosis and vesiculation. The dynamic coupling of the inner or cytoplasmic and outer or exofacial leaflets is a challenging open question in membrane biology. Here, we combined fluorescence lifetime imaging microscopy (FLIM) with imaging total internal reflection fluorescence correlation spectroscopy (ITIR-FCS) to differentiate the dynamics and organization of the two leaflets of live mammalian cells. We characterized the biophysical properties of fluorescent analogs of phosphatidylcholine, sphingomyelin, and phosphatidylserine in the plasma membrane of two mammalian cell lines (CHO-K1 and RBL-2H3). Because of their specific transverse membrane distribution, these probes allowed leaflet-specific investigation of the plasma membrane. We compared the results of the two methods having different temporal and spatial resolution. Fluorescence lifetimes of fluorescent lipid analogs were in ranges characteristic for the liquid ordered phase in the outer leaflet and for the liquid disordered phase in the inner leaflet. The observation of a more fluid inner leaflet was supported by free diffusion in the inner leaflet, with high average diffusion coefficients. The liquid ordered phase in the outer leaflet was accompanied by slower diffusion and diffusion with intermittent transient trapping. Our results show that the combination of FLIM and ITIR-FCS with specific fluorescent lipid analogs is a powerful tool for investigating lateral and transbilayer characteristics of plasma membrane in live cell lines.

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