Fluorescence lifetime-based sensing of polymersome leakage

2017 ◽  
Vol 16 (2) ◽  
pp. 155-158 ◽  
Author(s):  
Stephan Wang ◽  
Zhong-Ren Chen
Keyword(s):  
Fluorescence Lifetime ◽  
Polymer Degradation ◽  
Fluorescence Technique ◽  
Fluorescence Lifetimes ◽  
Time Resolved Fluorescence ◽  
Time Resolved

The time-resolved fluorescence technique enables us to differentiate between polymer degradation and vesicle leakage by employing fluorescence lifetimes and their amplitudes.

scholarly journals Thulium-Doped Silica Fibers with Enhanced Fluorescence Lifetime and Their Application in Ultrafast Fiber Lasers

Fibers ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 66 ◽  
Author(s):  
Jakub Cajzl ◽  
Pavel Peterka ◽  
Maciej Kowalczyk ◽  
Jan Tarka ◽  
Grzegorz Sobon ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Fluorescence Lifetime ◽  
Energy Levels ◽  
Local Environment ◽  
Alumina Nanoparticles ◽  
Fluorescence Lifetimes ◽  
Transfer Coefficients ◽  
Relaxation Energy ◽  
Time Resolved ◽  
Conventional Solution

In this work we report on the thulium-doped silica-based optical fibers with increased fluorescence lifetime of the 3F4 level thanks to the modification of the local environment of thulium ions by high content of alumina. The determination of the cross-relaxation energy-transfer coefficients from the measurements of the fluorescence lifetimes of the 3F4 and 3H4 energy levels of Tm3+ ions in the experimentally prepared optical fiber is provided as well. Preforms of optical fibers were prepared either by conventional solution-doping of Tm3+ and Al3+ ions or by dispersion-doping of Tm3+ ions with alumina nanoparticles. Optical fibers were characterized by means of Tm, Al, and Ge concentrations, refractive index profiles, optical spectral absorption and luminescence, and by time-resolved fluorescence spectroscopy. Highly aluminium-codoped thulium silicate optical fibers exhibited fluorescence lifetimes of over ~500 μs with maximum value of 756 μs, which means a fluorescence lifetime enhancement when compared to the thulium-doped fibers reported elsewhere. We show an application of the thulium-doped fiber in a compact all-fiber ring laser that is passively mode-locked by using graphene-based saturable absorber. The output pulsewidth and repetition rate were 905 fs and 32.67 MHz, respectively.

scholarly journals Studies on the aggregation-induced emission of silole film and crystal by time-resolved fluorescence technique

2005 ◽  
Vol 402 (4-6) ◽  
pp. 468-473 ◽  
Author(s):  
Yan Ren ◽  
Yongqiang Dong ◽  
Jacky W.Y. Lam ◽  
Ben Zhong Tang ◽  
Kam Sing Wong
Keyword(s):  
Fluorescence Technique ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Aggregation Induced Emission

Improved maximum entropy method for the analysis of fluorescence spectroscopy data: evaluating zero-time shift and assessing its effect on the determination of fluorescence lifetimes

The Analyst ◽  
2015 ◽  
Vol 140 (24) ◽  
pp. 8138-8147 ◽  
Author(s):  
Rosario Esposito ◽  
Giuseppe Mensitieri ◽  
Sergio de Nicola
Keyword(s):  
Maximum Entropy ◽  
Maximum Entropy Method ◽  
Entropy Method ◽  
Lifetime Distribution ◽  
Time Shift ◽  
Fluorescence Lifetimes ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Zero Time

A new algorithm based on the Maximum Entropy Method (MEM) is proposed for recovering the lifetime distribution and the zero-time shift from experimental time-resolved fluorescence decays.

scholarly journals CHARACTERIZING FLUORESCENCE LIFETIME OF NAD(P)H IN HUMAN LEUKEMIC MYELOID CELLS AND MONONUCLEAR CELLS

2013 ◽  
Vol 06 (04) ◽  
pp. 1350042
Author(s):  
LI-SHENG LIN ◽  
LI-NA LIU ◽  
HUI-FANG HUANG ◽  
YUAN-ZHONG CHEN ◽  
BU-HONG LI ◽  
...  
Keyword(s):  
Fluorescence Lifetime ◽  
Mononuclear Cells ◽  
Relative Concentration ◽  
Myeloid Cells ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Fluorescence Lifetimes ◽  
Label Free ◽  
Time Resolved ◽  
Significant Difference ◽  
The Mean

The aim of this ex vivo study was to explore the potential of using the fluorescence lifetime of intracellular reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) as a label-free indicator to characterize the differences between human leukemic myeloid cells and normal mononuclear cells (MNC). The steady-state and time-resolved autofluorescence of two human leukemic myeloid cell lines (K562, HL60) and MNC were measured by a spectrofluorimeter. According to excitation–emission matrix (EEM) analysis, the optimal emission of NAD(P)H in these cells suspensions occurred at 445 nm. Furthermore, the fluorescence lifetimes of NAD(P)H in leukemic myeloid cells and MNC were determined by fitting the time-resolved autofluorescence data. The mean fluorescence lifetimes of NAD(P)H in K562, HL60, and MNC cells were 5.57 ± 1.19, 4.45 ± 0.71, and 7.31 ± 0.60 ns, respectively. There was a significant difference in the mean lifetime of NAD(P)H between leukemic myeloid cells and MNC (p < 0.05). The difference was essentially caused by the change in relative concentration of free and protein-bound NAD(P)H. This study suggests that the mean fluorescence lifetime of NAD(P)H might be a potential label-free indicator for differentiating leukemic myeloid cells from MNC.

scholarly journals Synthesis, Photophysics, and Solvatochromic Studies of an Aggregated-Induced-Emission Luminogen Useful in Bioimaging

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4932 ◽  
Author(s):  
Laura Espinar-Barranco ◽  
Marta Meazza ◽  
Azahara Linares-Perez ◽  
Ramon Rios ◽  
Jose Manuel Paredes ◽  
...  
Keyword(s):  
Fluorescence Lifetime ◽  
Fluorescence Emission ◽  
Fluorescence Lifetime Imaging ◽  
Selective Isolation ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Lifetime Imaging ◽  
Intracellular Compartments ◽  
Photophysical Behavior ◽  
Heterogeneous Matrix

Biological samples are a complex and heterogeneous matrix where different macromolecules with different physicochemical parameters cohabit in reduced spaces. The introduction of fluorophores into these samples, such as in the interior of cells, can produce changes in the fluorescence emission properties of these dyes, caused by the specific physicochemical properties of cells. This effect can be especially intense with solvatofluorochromic dyes, where changes in the polarity environment surrounding the dye can drastically change the fluorescence emission. In this article, we studied the photophysical behavior of a new dye and confirmed the aggregation-induced emission (AIE) phenomenon with different approaches, such as by using different solvent proportions, increasing the viscosity, forming micelles, and adding bovine serum albumin (BSA), through analysis of the absorption and steady-state and time-resolved fluorescence. Our results show the preferences of the dye for nonpolar media, exhibiting AIE under specific conditions through immobilization. Additionally, this approach offers the possibility of easily determining the critical micelle concentration (CMC). Finally, we studied the rate of spontaneous incorporation of the dye into cells by fluorescence lifetime imaging and observed the intracellular pattern produced by the AIE. Interestingly, different intracellular compartments present strong differences in fluorescence intensity and fluorescence lifetime. We used this difference to isolate different intracellular regions to selectively study these regions. Interestingly, the fluorescence lifetime shows a strong difference in different intracellular compartments, facilitating selective isolation for a detailed study of specific organelles.

scholarly journals In Vivo Resolution of Multiexponential Decays of Multiple Near-Infrared Molecular Probes by Fluorescence Lifetime-Gated Whole-Body Time-Resolved Diffuse Optical Imaging

2007 ◽  
Vol 6 (4) ◽  
pp. 7290.2007.00020 ◽  
Author(s):  
Walter Akers ◽  
Frederic Lesage ◽  
Dewey Holten ◽  
Samuel Achilefu
Keyword(s):  
Optical Imaging ◽  
Fluorescence Lifetime ◽  
Fluorescence Intensity ◽  
Near Infrared ◽  
Molecular Probes ◽  
Whole Body ◽  
Diffuse Optical Imaging ◽  
Fluorescence Lifetimes ◽  
Time Resolved

The biodistribution of two near-infrared fluorescent agents was assessed in vivo by time-resolved diffuse optical imaging. Bacteriochlorophyll a (BC) and cypate-glysine-arginine-aspartic acid-serine-proline-lysine-OH (Cyp-GRD) were administered separately or combined to mice with subcutaneous xenografts of human breast adenocarcinoma and slow-release estradiol pellets for improved tumor growth. The same excitation (780 nm) and emission (830 nm) wavelengths were used to image the distinct fluorescence lifetime distribution of the fluorescent molecular probes in the mouse cancer model. Fluorescence intensity and lifetime maps were reconstructed after raster-scanning whole-body regions of interest by time-correlated single-photon counting. Each captured temporal point-spread function (TPSF) was deconvolved using both a single and a multiexponental decay model to best determine the measured fluorescence lifetimes. The relative signal from each fluorophore was estimated for any region of interest included in the scanned area. Deconvolution of the individual TPSFs from whole-body fluorescence intensity scans provided corresponding lifetime images for comparing individual component biodistribution. In vivo fluorescence lifetimes were determined to be 0.8 ns (Cyp-GRD) and 2 ns (BC). This study demonstrates that the relative biodistribution of individual fluorophores with similar spectral characteristics can be compartmentalized by using the time-domain fluorescence lifetime gating method.

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