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fluorescence lifetime imaging microscopy

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https://www.readbyqxmd.com/read/28807980/cd177-modulates-human-neutrophil-migration-through-activation-mediated-integrin-and-chemoreceptor-regulation
#1
Ming Bai, Ricardo Grieshaber-Bouyer, Junxia Wang, Angela B Schmider, Zachary S Wilson, Liling Zeng, Olha Halyabar, Matthew D Godin, Hung N Nguyen, Anaïs Levescot, Pierre Cunin, Craig T Lefort, Roy J Soberman, Peter A Nigrovic
CD177 is a GPI-anchored protein expressed by a variable proportion of human neutrophils that mediates surface expression of the anti-neutrophil cytoplasmic antibody (ANCA) antigen proteinase 3. CD177 associates with β2 integrins and recognizes PECAM-1, suggesting a role in neutrophil migration. However, CD177(pos) neutrophils exhibit no clear migratory advantage in vivo, despite interruption of transendothelial migration by in vitro CD177 ligation. We sought to understand this paradox. Using a PECAM-1-independent transwell system, we found that CD177(pos) and CD177(neg) neutrophils migrated comparably...
August 14, 2017: Blood
https://www.readbyqxmd.com/read/28792278/astrocytic-endfoot-ca-2-correlates-with-parenchymal-vessel-responses-during-4-ap-induced-epilepsy-an-in%C3%A2-vivo-two-photon-lifetime-microscopy-study
#2
Cong Zhang, Maryam Tabatabaei, Samuel Bélanger, Hélène Girouard, Mohammad Moeini, Xuecong Lu, Frédéric Lesage
Neurovascular coupling (NVC) underlying the local increase in blood flow during neural activity forms the basis of functional brain imaging and is altered in epilepsy. Because astrocytic calcium (Ca(2+)) signaling is involved in NVC, this study investigates the role of this pathway in epilepsy. Here, we exploit 4-AP induced epileptic events to show that absolute Ca(2+) concentration in cortical astrocyte endfeet in vivo correlates with the diameter of precapillary arterioles during neural activity. We simultaneously monitored free Ca(2+) concentration in astrocytic endfeet with the Ca(2+)-sensitive indicator OGB-1 and diameter of adjacent arterioles in the somatosensory cortex of adult mice by two-photon fluorescence lifetime measurements following 4-AP injection...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28774048/tissue-like-phantoms-as-a-platform-for-inserted-fluorescence-nano-probes
#3
Tsviya Nayhoz, Eran A Barnoy, Dror Fixler
Tissue-like phantoms are widely used as a model for mimicking the optical properties of live tissue. This paper presents the results of a diffusion reflection method and fluorescence lifetime imaging microscopy measurements of fluorescein-conjugated gold nanorods in solution, as well as inserted in solid tissue-imitating phantoms. A lack of consistency between the fluorescence lifetime results of the solutions and the phantoms raises a question about the ability of tissue-like phantoms to maintain the optical properties of inserted contrast agents...
November 15, 2016: Materials
https://www.readbyqxmd.com/read/28763194/enhanced-visualization-of-hematoxylin-and-eosin-stained-pathological-characteristics-by-phasor-approach
#4
Teng Luo, Yuan Lu, Shaoxiong Liu, Danying Lin, Junle Qu
The phasor approach to fluorescence lifetime imaging microscopy (FLIM) is used to identify different types of tissues from hematoxylin and eosin (H&E) stained basal cell carcinoma (BCC) sections. The results suggest that working directly on the phasor space with the clustering assignment achieves immunofluorescence like simultaneous five or six-color imaging by using multiplexed fluorescence lifetimes of H&E. The phase approach is of particular effectiveness for enhanced visualization of the abnormal morphology of a suspected nidus...
August 16, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28754922/shadowy-a-dark-yellow-fluorescent-protein-for-flim-based-fret-measurement
#5
Hideji Murakoshi, Akihiro C E Shibata
Fluorescence lifetime imaging microscopy (FLIM)-based Förster resonance energy transfer (FRET) measurement (FLIM-FRET) is one of the powerful methods for imaging of intracellular protein activities such as protein-protein interactions and conformational changes. Here, using saturation mutagenesis, we developed a dark yellow fluorescent protein named ShadowY that can serve as an acceptor for FLIM-FRET. ShadowY is spectrally similar to the previously reported dark YFP but has a much smaller quantum yield, greater extinction coefficient, and superior folding property...
July 28, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28749340/super-resolution-imaging-of-synaptic-and-extra-synaptic-ampa-receptors-with-different-sized-fluorescent-probes
#6
Sang Hak Lee, Chaoyi Jin, En Cai, Pinghua Ge, Yuji Ishitsuka, Kai Wen Teng, Andre A de Thomaz, Duncan L Nall, Murat Baday, Okunola Jeyifous, Daniel Demonte, Christopher M Dundas, Sheldon Park, Jary Y Delgado, William N Green, Paul R Selvin
Previous studies tracking AMPA receptor (AMPAR) diffusion at synapses observed a large mobile extrasynaptic AMPAR pool. Using super-resolution microscopy, we examined how fluorophore size and photostability affected AMPAR trafficking outside of, and within, post-synaptic densities (PSDs) from rats. Organic fluorescent dyes (≈4 nm), quantum dots, either small (≈10 nm diameter; sQDs) or big (>20 nm; bQDs), were coupled to AMPARs via different-sized linkers. We find that >90% of AMPARs labeled with fluorescent dyes or sQDs were diffusing in confined nanodomains in PSDs, which were stable for 15 minutes or longer...
July 27, 2017: ELife
https://www.readbyqxmd.com/read/28723155/inhibiting-the-fibrillation-of-serum-albumin-proteins-in-the-presence-of-surface-active-ionic-liquids-sails-at-low-ph-spectroscopic-and-microscopic-study
#7
Sangita Kundu, Chiranjib Banerjee, Nilmoni Sarkar
One of the key necessary steps to prevent human neurological disorders is the efficient disruption of protein aggregation or amyloid fibril. In this article, we have explored the effect of three amphiphilic surface active ionic liquids (SAILs), namely 1-methyl-3-octylimidazolium chloride ([C8mim]Cl), 1-dodecyl-3-methyllimidazolium chloride ([C12mim]Cl), and 1-hexadecyl-3-methyllimidazolium chloride ([C16mim]Cl) having concentrations of 5.8, 0.29, and 0.08 mM, respectively, on bovine serum albumin (BSA) and human serum albumin (HSA) fibril...
August 4, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28718466/exploring-viscosity-polarity-and-temperature-sensitivity-of-bodipy-based-molecular-rotors
#8
Aurimas Vyšniauskas, Ismael López-Duarte, Nicolas Duchemin, Thanh-Truc Vu, Yilei Wu, Ekaterina M Budynina, Yulia A Volkova, Eduardo Peña Cabrera, Diana E Ramírez-Ornelas, Marina K Kuimova
Microviscosity is a key parameter controlling the rate of diffusion and reactions on the microscale. One of the most convenient tools for measuring microviscosity is by fluorescent viscosity sensors termed 'molecular rotors'. BODIPY-based molecular rotors in particular proved extremely useful in combination with fluorescence lifetime imaging microscopy, for providing quantitative viscosity maps of living cells as well as measuring dynamic changes in viscosity over time. In this work, we investigate several new BODIPY-based molecular rotors with the aim of improving on the current viscosity sensing capabilities and understanding how the structure of the fluorophore is related to its function...
July 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28717559/measuring-the-effect-of-a-western-diet-on-liver-tissue-architecture-by-flim-autofluorescence-and-harmonic-generation-microscopy
#9
Suman Ranjit, Alexander Dvornikov, Evgenia Dobrinskikh, Xiaoxin Wang, Yuhuan Luo, Moshe Levi, Enrico Gratton
The phasor approach to auto-fluorescence lifetime imaging was used to identify and characterize a long lifetime species (LLS) (~7.8 ns) in livers of mice fed with a Western diet. The size of the areas containing this LLS species depends on the type of diet and the size distribution shows Western diet has much larger LLS sizes. Combination of third harmonic generation images with FLIM identified the LLS species with fat droplets and the droplet size distribution was estimated. Second harmonic generation microscopy combined with phasor FLIM shows that there is an increase in fibrosis with a Western diet...
July 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28717558/single-pulse-two-photon-fluorescence-lifetime-imaging-sp-flim-with-mhz-pixel-rate
#10
Matthias Eibl, Sebastian Karpf, Daniel Weng, Hubertus Hakert, Tom Pfeiffer, Jan Philip Kolb, Robert Huber
Two-photon-excited fluorescence lifetime imaging microscopy (FLIM) is a chemically specific 3-D sensing modality providing valuable information about the microstructure, composition and function of a sample. However, a more widespread application of this technique is hindered by the need for a sophisticated ultra-short pulse laser source and by speed limitations of current FLIM detection systems. To overcome these limitations, we combined a robust sub-nanosecond fiber laser as the excitation source with high analog bandwidth detection...
July 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28700140/development-of-a-molecular-bio-switch-using-fluorescence-lifetime-imaging-incremental-activation-of-fluorescein-diacetate
#11
Eran A Barnoy, Rachela Popovtzer, Dror Fixler
Molecular bio-switches offer an invaluable asset in the shift from systemic to targeted treatments. Within the growing arsenal of switches are imaging probes that functionalize only in given locations or situations. Acetate esters are a common fluorescent example, known to activate upon interaction with esterases. Fluorescein diacetate (FDA) is one such fluorophore used in cell viability assays. These assays rely on the fact that the compound begins colorless and with no fluorescent signature whatsoever, and only after internalization into cells it is possible to detect a fluorescence signal...
July 12, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28697597/core-assisted-formation-of-porphyrin-j-aggregates-in-ph-sensitive-polyelectrolyte-microcapsules-followed-by-fluorescence-lifetime-imaging-microscopy
#12
Vanda Vaz Serra, Nuno G B Neto, Suzana M Andrade, Sílvia M B Costa
A strategy assisted by an inorganic template was developed to promote the organized self-assembly of meso-(tetrakis)-(p-sulfonatophenyl)porphyrin (TPPS) on pH-sensitive core-shell polyelectrolyte microcapsules (PECs) of poly(styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH). A key feature of this strategy is the use of template CaCO3 microparticles as a nucleation site endorsing inside-outside directional growth of porphyrin aggregates. Using this approach, TPPS self-assembly in positively charged PECs with CaCO3 (PAH/PSS)2PAH as a sequence of layers was successfully achieved using mild pH conditions (pH 3)...
July 28, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28689079/different-molecular-organization-of-two-carotenoids-lutein-and-zeaxanthin-in-human-colon-epithelial-cells-and-colon-adenocarcinoma-cells
#13
Wojciech Grudzinski, Mateusz Piet, Rafal Luchowski, Emilia Reszczynska, Renata Welc, Roman Paduch, Wieslaw I Gruszecki
Two cell lines, human normal colon epithelial cells (CCD 841 CoTr) and human colon adenocarcinoma cells (HT-29) were cultured in the presence of exogenous carotenoids, either zeaxanthin or lutein. Both carotenoids demonstrated cytotoxicity with respect to cancer cells but not to normal cells. Cells from both the cell lines were analyzed with application of fluorescence lifetime imaging microscopy and Raman scattering microscopy. Both imaging techniques show effective incorporation of carotenoid molecules into growing cells...
July 5, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28686582/measurement-of-drug-target-engagement-in-live-cells-by-two-photon-fluorescence-anisotropy-imaging
#14
Claudio Vinegoni, Paolo Fumene Feruglio, Christian Brand, Sungon Lee, Antoinette E Nibbs, Shawn Stapleton, Sunil Shah, Ignacy Gryczynski, Thomas Reiner, Ralph Mazitschek, Ralph Weissleder
The ability to directly image and quantify drug-target engagement and drug distribution with subcellular resolution in live cells and whole organisms is a prerequisite to establishing accurate models of the kinetics and dynamics of drug action. Such methods would thus have far-reaching applications in drug development and molecular pharmacology. We recently presented one such technique based on fluorescence anisotropy, a spectroscopic method based on polarization light analysis and capable of measuring the binding interaction between molecules...
July 2017: Nature Protocols
https://www.readbyqxmd.com/read/28684722/overview-of-single-molecule-speckle-sims-microscopy-and-its-electroporation-based-version-with-efficient-labeling-and-improved-spatiotemporal-resolution
#15
REVIEW
Sawako Yamashiro, Naoki Watanabe
Live-cell single-molecule imaging was introduced more than a decade ago, and has provided critical information on remodeling of the actin cytoskeleton, the motion of plasma membrane proteins, and dynamics of molecular motor proteins. Actin remodeling has been the best target for this approach because actin and its associated proteins stop diffusing when assembled, allowing visualization of single-molecules of fluorescently-labeled proteins in a state specific manner. The approach based on this simple principle is called Single-Molecule Speckle (SiMS) microscopy...
July 6, 2017: Sensors
https://www.readbyqxmd.com/read/28672397/structural-and-functional-characterization-of-human-stem-cell-derived-retinal-organoids-by-live-imaging
#16
REVIEW
Andrew W Browne, Cosimo Arnesano, Narine Harutyunyan, Thien Khuu, Juan Carlos Martinez, Harvey A Pollack, David S Koos, Thomas C Lee, Scott E Fraser, Rex A Moats, Jennifer G Aparicio, David Cobrinik
Purpose: Human pluripotent stem cell (hPSC)-derived retinal organoids are a platform for investigating retinal development, pathophysiology, and cellular therapies. In contrast to histologic analysis in which multiple specimens fixed at different times are used to reconstruct developmental processes, repeated analysis of the same living organoids provides a more direct means to characterize changes. New live imaging modalities can provide insights into retinal organoid structure and metabolic function during in vitro growth...
July 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28663908/transient-absorption-imaging-of-hemes-with-2-color-independently-tunable-visible-wavelength-ultrafast-source
#17
Scott R Domingue, Randy A Bartels, Adam J Chicco, Jesse W Wilson
Pump probe microscopy is a time-resolved multiphoton imaging technique capable of generating contrast between non-fluorescent pigments based on differences in excited-state lifetimes. Here we describe a fiber-based ultrafast system designed for imaging heme proteins with an independently-tunable pulse pair in the visible-wavelength regime. Starting with a 1060 nm fiber amplifier (1.3 W at 63 MHz, 140 fs pulses), visible pulses were produced in the vicinity of 488 nm and 532 nm by doubling the output of a short photonic crystal fiber with a pair of periodically-poled lithium niobate crystals, providing 5-20 mW power in each beam...
June 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28663879/fluorescence-lifetime-microscopy-of-nadh-distinguishes-alterations-in-cerebral-metabolism-in-vivo
#18
Mohammad A Yaseen, Jason Sutin, Weicheng Wu, Buyin Fu, Hana Uhlirova, Anna Devor, David A Boas, Sava Sakadžić
Evaluating cerebral energy metabolism at microscopic resolution is important for comprehensively understanding healthy brain function and its pathological alterations. Here, we resolve specific alterations in cerebral metabolism in vivo in Sprague Dawley rats utilizing minimally-invasive 2-photon fluorescence lifetime imaging (2P-FLIM) measurements of reduced nicotinamide adenine dinucleotide (NADH) fluorescence. Time-resolved fluorescence lifetime measurements enable distinction of different components contributing to NADH autofluorescence...
May 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28663873/autofluorescence-imaging-captures-heterogeneous-drug-response-differences-between-2d-and-3d-breast-cancer-cultures
#19
T M Cannon, A T Shah, M C Skala
Two-photon microscopy of cellular autofluorescence intensity and lifetime (optical metabolic imaging, or OMI) is a promising tool for preclinical drug development. OMI, which exploits the endogenous fluorescence from the metabolic coenzymes NAD(P)H and FAD, is sensitive to changes in cell metabolism produced by drug treatment. Previous studies have shown that drug response, genetic expression, cell-cell communication, and cell signaling in 3D culture match those of the original in vivo tumor, but not those of 2D culture...
March 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28663841/optically-sectioned-wide-field-fluorescence-lifetime-imaging-microscopy-enabled-by-structured-illumination
#20
Taylor Hinsdale, Cory Olsovsky, Jose J Rico-Jimenez, Kristen C Maitland, Javier A Jo, Bilal H Malik
In this paper, we demonstrate the ability of structured illumination microscopy to enhance the ability of fluorescence lifetime imaging to resolve fluorescence lifetimes in relatively thick samples that possess distinct but spectrally overlapping fluorescent layers. Structured illumination fluorescent lifetime imaging microscopy (SI-FLIM) is shown to be able to accurately reconstruct lifetime values in homogenous fluorophore samples (POPOP, NADH, and FAD) as well as accurately measure fluorescent lifetime in two layer models that are layered with NADH/FAD over POPOP, where NADH/FAD and POPOP have spectral overlap...
March 1, 2017: Biomedical Optics Express
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