Analysis of fluorescence decay kinetics from variable-frequency phase shift and modulation data

Lakowicz, Joseph R.; Laczko, Gabor; Cherek, Henryk; Gratton, Enrico; Limkeman, Mark

doi:10.1016/s0006-3495(84)84043-6

Cited by 441 publications

(260 citation statements)

References 17 publications

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“…Fluorescence lifetime data analysis was performed with the above computer system using a nonlinear least-squares routine for multiexponential fitting [30] and ISSOl software (ISS, Urbana). In the nonlinear least-squares method, the data were fitted to one or multiple exponential terms.…”

Section: Lifetime Nonlinear Least-squares Analysismentioning

confidence: 99%

“…The number of fluorescent lifetime components was highly depen- Table 1 Effect of cholestatrienol purity on lifetime analysis in POPC suv Lifetime of 2 mol$ cholestatrienol in POPC SW was measured at 24°C by phase and modulation techniques at 5,10,20,30,4O,50,60,70,SO,90,100,115,120,140 Table 2 concentration, only a single lifetime component at 0.392 + 0.004 ns was resolved. Above the critical micellar concentration in ethanol a second component near 5 ns appeared, with increasing fractional intensity at higher cholestatrienol concentrations above the critical micelle concentration.…”

Section: Multifrequencymentioning

confidence: 99%

“…The limiting anisotropy of cholestatrienol (0.5 mol%) of POPC SUV was determined with the multifrequency (l-250 MHz) phase and modulation instruments using 14 different frequencies (10,20,30,40,60,70,80,90,100,115,120,130,140 and 150 MHz). The limiting anisotropy thereby obtained and the rotational rate calculated according to the equations developed by Lakowicz et al [36] were 0.170 and 0.41 radian/m, respectively, at 24°C ( fig.…”

Section: Dependence Of Limiting Anisotropy and Rotational Rate On Chomentioning

confidence: 99%

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Fluorescence properties of cholestatrienol in phosphatidylcholine bilayer vesicles

Schroeder

Nemecz

Gratton

et al. 1988

Biophysical Chemistry

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The fluorescent sterol A5~7~g*~")-cholestatrien-3&ol (cholestatrienol) was incorporated into l-pahnitoyl-2-oleoyl-phosphatidylcholine (POPC) small unilamellar vesicles (WV) with and without cholesterol in order to monitor sterol-sterol interactions in model membranes. Previously another fluorescent sterol, dehydroergosterol (F. Schroeder, Y. Barenholz, E. Gratton and T.E. Thompson, Biochemistry 26 (1987) 2441), was used for this purpose. However, there is some concern that dehydroergosterol may not be the best analogue for cholesterol. Fluorescence properties of cholestatrienol in POPC SW were highly sensitive to cholestatrienol purity. The fluorescence decay of cholestatienol in the POPC SUV was analyzed by assuming either that the decay is comprised of a discrete sum of exponential components or that the decay is made up of one or more component's distribution of lifetimes. The decay for cholestatrienol in POPC SUV analyzed using distributions had a lower x2 value and was described by a two-component Lorentzian function with centers near 0.86 and 3.24 ns, and fractional intensities of 0.96 and 0.04, respectively. Both distributions were quite narrow, i.e., 0.05 ns full-width at half-maximum peak height. It is proposed that the two lifetime distributions are generated by separate continua of environments for the cholestatrienol molecule described by different dielectric constants. In the range O-6 mol% cholestatrienol, the cholestatrienol underwent a concentration-dependent relaxation. This process was characterized by red-shifted absorption and maxima and altered ratios of absorption and fluorescence excitation maxima. Fluorescence quantum yield, lifetime, steady-state anisotropy, limiting anisotropy and rotational rate remained constant. In contrast, in POPC vesicles containing between 6 and 33 mol% cholestatrienol, the fluorescent cholestatrienol partially segregated, resulting in quenching. Thus, below 6 mot% cholestatienol, the cholestatrienol appeared to behave in part as monomers exposed to some degree to the aqueous solvent in a sterol-poor domain within POPC bilayers. Sin= the lifetime did not decrease above 6 molX cholestatrienol, the fluorescence at high mol% values of cholestatrienol was due to cholestatrienol in the sterol-poor domain. The fluorescence intensity, quantum yield, steady-state anisotropy, and limiting anisotropy of cholestatrienol in the sterol-poor domain decreased to limiting, nonzero values while the rotational rate increased to a limiting value. Thus, the sterol-poor domain became more disordered when it coexisted with the sterol-rich domain. In POPC vesicles containing 3 mol% cholestatrienol plus increasing mol% cholesterol the two sterols codistributed, since fluorescence quenching was not observed. Above 6 mol% total sterol the cholestatrienol was sensitive to sterol motional properties in the laterally segregated sterol-rich domain. The sterol-rich domain became more rigid with increasing cholesterol content of the POPC SUV. The data are consistent with the presence of a r...

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Section: Lifetime Nonlinear Least-squares Analysismentioning

confidence: 99%

Section: Multifrequencymentioning

confidence: 99%

Section: Dependence Of Limiting Anisotropy and Rotational Rate On Chomentioning

confidence: 99%

See 1 more Smart Citation

Fluorescence properties of cholestatrienol in phosphatidylcholine bilayer vesicles

Schroeder

Nemecz

Gratton

et al. 1988

Biophysical Chemistry

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“…16 The multiexponential model is used to describe the form of the intensity decay. We are not assigning molecular significance to the recovered parameters.…”

Section: Fluorescence Measurementsmentioning

confidence: 99%

Surface Plasmon-Coupled Ultraviolet Emission of 2,5-Diphenyl-1,3,4-oxadiazole

Malicka

Gryczyński

et al. 2004

J. Phys. Chem. B

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We studied surface plasmon-coupled emission (SPCE) of 2,5-diphenyl-1,3,4-oxadiazole (PPD) using a 20 nm aluminum film deposited on a quartz substrate. The directional SPCE UV fluorescence occurs within a narrow angle at 57° from the normal to the coupling hemicylindrical prism. This radiation is almost completely p-polarized, consistent with its origin from surface plasmons. These surface plasmons are induced by excited PPD molecules. The coupling of excited fluorophore dipoles with the aluminum is highly efficient, exceeding 50%. Different fluorescence emission wavelengths are emitted at slightly different angles on the prism, providing intrinsic spectral resolution. SPCE fluorescence on thin aluminum films can be used with many UV absorbing and emitting fluorophores.

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“…The major alternative to the TCSPC method for lifetime determination is the widely used Frequency Domain (FD) methodology [15][16][17]. This method is potentially more useful for complex fluid analysis, since the data analysis can be more straightforward and rapid than for TCSPC.…”

Section: Introductionmentioning

confidence: 99%

Frequency Domain Fluorescence Lifetime Study of Crude Petroleum Oils

2008

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Abstract:Frequency domain (FD) fluorescence lifetime data was collected for a series of 20 crude petroleum oils using a 405 nm excitation source and over a spectral range of ~426 to ~650 nm. Average fluorescence lifetimes were calculated using three different models: discrete multi-exponential, Gaussian distribution, and Lorentzian distribution. Fitting the data to extract accurate average lifetimes using the various models proved easier and less time consuming for the FD data than with Time Correlated Single Photon Counting (TCSPC) methods however the analysis of confidence intervals to the computed average lifetimes proved cumbersome for both methods. The uncertainty in the average lifetime was generally larger for the discrete lifetime multi-exponential model when compared to the distributionbased models. For the lifetime distributions, the data from the light crude oils with long lifetimes generally fit to a single decay term. Heavier oils with shorter lifetimes required This is the author version of the paper: Frequency Domain Fluorescence Lifetime Study of Crude Petroleum Oils. P. Owens, A.G. Ryder, and N.J.F. Blamey. Journal of Fluorescence, 18(5), 997-1006Fluorescence, 18(5), 997- , (2008. DOI: 10.1007/s10895-008-0330-5Page 2 of 21 multiple decay terms. The actual value for the average lifetime is more dependant on the exact fitting model employed than the data acquisition method used. Correlations between average fluorescence lifetimes and physical and chemical parameters of the crude oils were made with a view to developing a quantitative model for predicting the gross chemical composition of crude oils. It was found that there was no significant benefit gained by using FD over TCSPC other than more rapid data analysis in the FD case. For the FD data the Gaussian distribution model for fluorescence lifetime gave the best correlations with chemical composition allowing a qualitative correlation to some bulk oil parameters.

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Analysis of fluorescence decay kinetics from variable-frequency phase shift and modulation data

Cited by 441 publications

References 17 publications

Fluorescence properties of cholestatrienol in phosphatidylcholine bilayer vesicles

Fluorescence properties of cholestatrienol in phosphatidylcholine bilayer vesicles

Surface Plasmon-Coupled Ultraviolet Emission of 2,5-Diphenyl-1,3,4-oxadiazole

Frequency Domain Fluorescence Lifetime Study of Crude Petroleum Oils

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