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fluorescence lifetime imaging microscopy

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https://www.readbyqxmd.com/read/28542327/efficient-up-conversion-in-yb-er-nat-xo4-2-thermal-nanoprobes-imaging-of-their-distribution-in-a-perfused-mouse
#1
Carlos Zaldo, María Dolores Serrano, Xiumei Han, Concepción Cascales, Marta Cantero, Lluís Montoliu, Elvira Arza, Valeria R Caiolfa, Moreno Zamai
Yb and Er codoped NaT(XO4)2 (T = Y, La, Gd, Lu and X = Mo, W) disordered oxides show a green (Er3+ related) up-conversion (UC) efficiency comparable to that of Yb:Er:β-NaYF4 compound and unless 3 times larger UC ratiometric thermal sensitivity. The similar UC efficiency of Yb:Er doped NaT(XO4)2 and β-NaYF4 compounds allowed testing equal subcutaneous depths of ex-vivo chicken tissue in both cases. This extraordinary behavior for NaT(XO4)2 oxides with large cutoff phonon energy (ħω≈ 920 cm-1) is ascribed to 4F9/2 electron population recycling to higher energy 4G11/2 level by a phonon assisted transition...
2017: PloS One
https://www.readbyqxmd.com/read/28540717/imaging-laser-triggered-drug-release-from-gold-nanocages-with-transient-absorption-lifetime-microscopy-talm
#2
Yongkui Xu, Qi Liu, Ruoyu He, Xianchong Miao, Minbiao Ji
Nanoparticles have shown promise in loading and delivering drugs for targeted therapy. Many progresses have been made in the design, synthesis and modification of nanoparticles to fulfill such goals. However, realizing targeted intracellular delivery and controlled release of drugs remain challenging, partly due to the lack of reliable tools to detect the drug releasing process. In this paper, we applied femtosecond laser pulses to trigger the explosion of gold nanocages (AuNCs) and controlled the intracellular release of loaded AlPcS molecules for photodynamic therapy (PDT)...
May 25, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28533371/blue-fluorescent-amino-acid-for-biological-spectroscopy-and-microscopy
#3
Mary Rose Hilaire, Ismail A Ahmed, Chun-Wei Lin, Hyunil Jo, William F DeGrado, Feng Gai
Many fluorescent proteins are currently available for biological spectroscopy and imaging measurements, allowing a wide range of biochemical and biophysical processes and interactions to be studied at various length scales. However, in applications where a small fluorescence reporter is required or desirable, the choice of fluorophores is rather limited. As such, continued effort has been devoted to the development of amino acid-based fluorophores that do not require a specific environment and additional time to mature and have a large fluorescence quantum yield, long fluorescence lifetime, good photostability, and an emission spectrum in the visible region...
May 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28524818/fluorescence-lifetime-imaging-microscopy-reveals-rerouting-of-snare-trafficking-driving-dendritic-cell-activation
#4
Daniëlle Rianne José Verboogen, Natalia González Mancha, Martin Ter Beest, Geert van den Bogaart
SNARE proteins play a crucial role in intracellular trafficking by catalyzing membrane fusion, but assigning SNAREs to specific intracellular transport routes is challenging with current techniques. We developed a novel Förster resonance energy transfer-fluorescence lifetime imaging microscopy (FRET-FLIM)-based technique allowing visualization of real-time local interactions of fluorescently tagged SNARE proteins in live cells. We used FRET-FLIM to delineate the trafficking steps underlying the release of the inflammatory cytokine interleukin-6 (IL-6) from human blood-derived dendritic cells...
May 19, 2017: ELife
https://www.readbyqxmd.com/read/28514858/a-cholesterol-based-surface-active-ionic-liquid-that-can-form-microemulsions-and-spontaneous-vesicles
#5
Arghajit Pyne, Jagannath Kuchlyan, Chiranjit Maiti, Dibakar Dhara, Nilmoni Sarkar
In this article, we have reported the synthesis and physicochemical characterization of a novel L-glycine amino acid derived cholesterol based surface active ionic liquid (SAIL). This SAIL has been explored for the preparation of ionic liquid (IL)-in-oil microemulsions and vesicles. The formation of IL-in-oil microemulsion is characterized by construction of a ternary phase diagram, dynamic light scattering (DLS) measurement, proton nuclear magnetic resonance (1H NMR) study, fluorescence measurement using coumarin 480 (C-480) as a molecular probe and also by recording the diffusion behavior of the molecular probe rhodamine 6G (R6G) in microemulsion droplets through Fluorescence correlation spectroscopy (FCS) technique...
May 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28487417/tetraspanin-microdomains-control-localized-protein-kinase-c-signaling-in-b-cells
#6
Malou Zuidscherwoude, Vera-Marie E Dunlock, Geert van den Bogaart, Sjoerd J van Deventer, Alie van der Schaaf, Jenny van Oostrum, Joachim Goedhart, Joanna In 't Hout, Günter J Hämmerling, Satoshi Tanaka, André Nadler, Carsten Schultz, Mark D Wright, Merel J W Adjobo-Hermans, Annemiek B van Spriel
Activation of B cells by the binding of antigens to the B cell receptor (BCR) requires the protein kinase C (PKC) family member PKCβ. Because PKCs must translocate to the plasma membrane to become activated, we investigated the mechanisms regulating their spatial distribution in mouse and human B cells. Through live-cell imaging, we showed that BCR-stimulated production of the second messenger diacylglycerol (DAG) resulted in the translocation of PKCβ from the cytosol to plasma membrane regions containing the tetraspanin protein CD53...
May 9, 2017: Science Signaling
https://www.readbyqxmd.com/read/28485124/autofluorescence-imaging-identifies-tumor-cell-cycle-status-on-a-single-cell-level
#7
Tiffany M Heaster, Alex J Walsh, Yue Zhao, Scott W Hiebert, Melissa C Skala
The goal of this study is to validate fluorescence intensity and lifetime imaging of metabolic co-enzymes NAD(P)H and FAD (optical metabolic imaging, or OMI) as a method to quantify cell-cycle status of tumor cells. Heterogeneity in tumor cell-cycle status (e. g. proliferation, quiescence, apoptosis) increases drug resistance and tumor recurrence. Cell-cycle status is closely linked to cellular metabolism. Thus, this study applies cell-level metabolic imaging to distinguish proliferating, quiescent, and apoptotic populations...
May 9, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28485056/quantifying-intracellular-equilibrium-dissociation-constants-using-single-channel-time-resolved-fret
#8
Gloria de Las Heras-Martínez, Josu Andrieu, Banafshé Larijani, Jose Requejo-Isidro
Quantification of the intracellular equilibrium dissociation constant of the interaction, Kd , is challenging due to the variability of the relative concentrations of the interacting proteins in the cell. Fluorescence lifetime imaging microscopy (FLIM) of the donor provides an accurate measurement of the molecular fraction of donor involved in FRET, but the fraction of bound acceptor is also needed to reliably estimate Kd . We present a method that exploits the spectroscopic properties of the widely used eGFP - mCherry FRET pair to rigorously determine the intracellular Kd based on imaging the fluorescence lifetime of only the donor (single-channel FLIM)...
May 9, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28484480/single-event-resolution-of-plant-plasma-membrane-protein-endocytosis-by-tirf-microscopy
#9
Alexander Johnson, Grégory Vert
Endocytosis is a key process in the internalization of extracellular materials and plasma membrane proteins, such as receptors and transporters, thereby controlling many aspects of cell signaling and cellular homeostasis. Endocytosis in plants has an essential role not only for basic cellular functions but also for growth and development, nutrient delivery, toxin avoidance, and pathogen defense. The precise mechanisms of endocytosis in plants remain quite elusive. The lack of direct visualization and examination of single events of endocytosis has greatly hampered our ability to precisely monitor the cell surface lifetime and the recruitment profile of proteins driving endocytosis or endocytosed cargos in plants...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28452360/an-intermolecular-fret-sensor-detects-the-dynamics-of-t-cell-receptor-clustering
#10
Yuanqing Ma, Elvis Pandzic, Philip R Nicovich, Yui Yamamoto, Joanna Kwiatek, Sophie V Pageon, Aleš Benda, Jérémie Rossy, Katharina Gaus
Clustering of the T-cell receptor (TCR) is thought to initiate downstream signalling. However, the detection of protein clustering with high spatial and temporal resolution remains challenging. Here we establish a Förster resonance energy transfer (FRET) sensor, named CliF, which reports intermolecular associations of neighbouring proteins in live cells. A key advantage of the single-chain FRET sensor is that it can be combined with image correlation spectroscopy (ICS), single-particle tracking (SPT) and fluorescence lifetime imaging microscopy (FLIM)...
April 28, 2017: Nature Communications
https://www.readbyqxmd.com/read/28444700/fluorescence-lifetime-imaging-and-super-resolution-microscopies-shed-light-on-the-directed-and-self-assembly-of-functional-porphyrins-onto-carbon-nanotubes-and-flat-surfaces
#11
Boyang Mao, David González Calatayud, Vincenzo Mirabello, Haobo Ge, Benjamin J Hodges, Robert M J Jacobs, Ashley M Shepherd, José Alberto Ribeiro Martins, Navaratnarajah Kuganathan, Jorge Bernardino De La Serna, Stanley W Botchway, Sofia Ioana Pascu
Two new routes to functionalized SWNTs have been established using a bulky Zn(II)-porphyrin featuring thiolate groups at the periphery. We probed the optical properties of this Zinc(II)-substituted, bulky aryl porphyrin and those of the corresponding new nano-composites with single walled carbon nanotube (SWNTs) and coronene, as a model for graphene. We report hereby on: (i) the supramolecular interactions between the pristine SWNTs and Zn(II)-porphyrin by virtue of π-π stacking, and (ii) a novel covalent binding strategy based on the Bingel reaction...
April 25, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28439869/studying-protein-protein-interactions-in-planta-using-advanced-fluorescence-microscopy
#12
Marc Somssich, Rüdiger Simon
The formation of protein complexes through direct protein-protein interaction is essential for virtually every biological process, and accordingly the ability to determine the interaction properties of specific proteins is important to understand these processes. Förster resonance energy transfer (FRET) measurements are state-of-the-art confocal fluorescence microscopy- and imaging-based techniques that allow the analysis of protein interactions in vivo and in planta, in specific compartments of single cells or tissues...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28434902/intravital-microscopy-of-biosensor-activities-and-intrinsic-metabolic-states
#13
REVIEW
Seth Winfree, Takashi Hato, Richard N Day
Intravital microscopy (IVM) is an imaging tool that is capable of detecting subcellular signaling or metabolic events as they occur in tissues in the living animal. Imaging in highly scattering biological tissues, however, is challenging because of the attenuation of signal in images acquired at increasing depths. Depth-dependent signal attenuation is the major impediment to IVM, limiting the depth from which significant data can be obtained. Therefore, making quantitative measurements by IVM requires methods that use internal calibration, or alternatively, a completely different way of evaluating the signals...
April 21, 2017: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/28374909/doxorubicin-loaded-chitosan-w18-o49-hybrid-nanoparticles-for-combined-photothermal-chemotherapy
#14
Shanmei Yuan, Jisong Hua, Yinyin Zhou, Yin Ding, Yong Hu
Combined treatment is more effective than single treatment against most forms of cancer. In this work, doxorubicin loaded chitosan-W18 O49 nanoparticles combined with the photothermal therapy and chemotherapy are fabricated through the electrostatic interaction between positively charged chitosan and negatively charged W18 O49 nanoparticles. The in vitro and in vivo behaviors of these nanoparticles are examined by dynamic light scattering, transmission electron microscopy, cytotoxicity, near-infrared fluorescence imaging, and tumor growth inhibition experiment...
April 4, 2017: Macromolecular Bioscience
https://www.readbyqxmd.com/read/28369765/method-to-detect-the-cellular-source-of-over-activated-nadph-oxidases-using-nad-p-h-fluorescence-lifetime-imaging
#15
Daniel Bremer, Ruth Leben, Ronja Mothes, Helena Radbruch, Raluca Niesner
Fluorescence-lifetime imaging microscopy (FLIM) is a technique to generate images, in which the contrast is obtained by the excited-state lifetime of fluorescent molecules instead of their intensity and emission spectrum. The ubiquitous coenzymes NADH and NADPH, hereafter NAD(P)H, in cells show a short fluorescence lifetime ≈400 psec in the free-state and a longer fluorescence lifetime when bound to enzymes. The fluorescence lifetime of NAD(P)H in this state depends on the binding-site on the specific enzyme...
April 3, 2017: Current Protocols in Cytometry
https://www.readbyqxmd.com/read/28362747/functional-in-vivo-imaging-using-fluorescence-lifetime-light-sheet-microscopy
#16
Claire A Mitchell, Simon P Poland, James Seyforth, Jakub Nedbal, Thomas Gelot, Tahiyat Huq, Gerhard Holst, Robert D Knight, Simon M Ameer-Beg
Light-sheet microscopy has become an indispensable tool for fast, low phototoxicity volumetric imaging of biological samples, predominantly providing structural or analyte concentration data in its standard format. Fluorescence lifetime imaging microscopy (FLIM) provides functional contrast, but often at limited acquisition speeds and with complex implementation. Therefore, we incorporate a dedicated frequency domain CMOS FLIM camera and intensity-modulated laser into a light-sheet setup to add fluorescence lifetime imaging functionality, allowing the rapid acquisition of volumetric data with concentration independent contrast...
April 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28323249/local-density-of-electromagnetic-states-in-plasmonic-nanotapers-spatial-resolution-limits-with-nitrogen-vacancy-centers-in-diamond-nanospheres
#17
Rafael Salas-Montiel, Martin Berthel, Josslyn Beltran-Madrigal, Serge Huant, Aurélien Drezet, Sylvain Blaize
One of the most explored single quantum emitters for the development of nanoscale fluorescence lifetime imaging is the nitrogen-vacancy (NV) color center in diamond. An NV center does not experience fluorescence bleaching or blinking at room temperature. Furthermore, its optical properties are preserved when embedded into nanodiamond hosts. This paper focuses on the modeling of the local density of states (LDOS) in a plasmonic nanofocusing structure with an NV center acting as local illumination sources. Numerical calculations of the LDOS near such a nanostructure were done with a classical electric dipole radiation placed inside a diamond sphere as well as near-field optical fluorescence lifetime imaging of the structure...
May 19, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28294329/multidie-led-combined-with-homogenizing-optics-to-improve-frequency-response-and-intensity-for-flim-applications
#18
H-T Liu, W-L Lin, Y-L Feng, Y Lin, Y-C Chen
Application of light-emitting diodes (LEDs) in frequency-domain fluorescence lifetime imaging microscopy (FLIM) has been limited by the trade-off between modulation frequency and illumination intensity of LEDs, which affects the signal-to-noise ratio in fluorescence lifetime measurements. To increase modulation frequency without sacrificing output power of LEDs, we propose to use LEDs with multiple dice connected in series. The LED capacitance was reduced with series connection; therefore, the frequency response of multidie LED was significantly increased...
March 15, 2017: Journal of Microscopy
https://www.readbyqxmd.com/read/28286806/assessment-of-cellular-redox-state-using-nad-p-h-fluorescence-intensity-and-lifetime
#19
Thomas S Blacker, Tunde Berecz, Michael R Duchen, Gyorgy Szabadkai
NADH and NADPH are redox cofactors, primarily involved in catabolic and anabolic metabolic processes respectively. In addition, NADPH plays an important role in cellular antioxidant defence. In live cells and tissues, the intensity of their spectrally-identical autofluorescence, termed NAD(P)H, can be used to probe the mitochondrial redox state, while their distinct enzyme-binding characteristics can be used to separate their relative contributions to the total NAD(P)H intensity using fluorescence lifetime imaging microscopy (FLIM)...
January 20, 2017: Bio-protocol
https://www.readbyqxmd.com/read/28285819/imaging-erk-and-pka-activation-in-single-dendritic-spines-during-structural-plasticity
#20
Shen Tang, Ryohei Yasuda
Extracellular signal-regulated kinase (ERK) and protein kinase A (PKA) play important roles in LTP and spine structural plasticity. While fluorescence resonance energy transfer (FRET)-based sensors for these kinases had previously been developed, they did not provide sufficient sensitivity for imaging small neuronal compartments, such as single dendritic spines in brain slices. Here we improved the sensitivity of FRET-based kinase sensors for monitoring kinase activity under two-photon fluorescence lifetime imaging microscopy (2pFLIM)...
March 22, 2017: Neuron
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