Time-resolved evanescent wave induced fluorescence spectroscopy. Part 1.—Deviations in the fluorescence lifetime of tetrasulphonated aluminium phthalocyanine at a fused silica/methanol interface

Rumbles, Garry; Brown, Alan J.; Phillips, David

doi:10.1039/ft9918700825

Cited by 28 publications

(18 citation statements)

References 31 publications

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“…A fluorophore, which acts as a probe that partitions into the interfacial region or is chemically grafted to a surface-specific species of interest, is photoexcited by the evanescent field, and the fluorescence spectrum is collected. Time-resolved evanescent waveinduced fluorescence spectroscopy (TREWIFS) measurements have provided fluorescence decay times, t f , of fluorescent species near an interface (30,31). The t f -value can report on the polarity of the microenvironment of the fluorophore, from which information on the structure of the interface or the behavior of surface species can be inferred.…”

Section: Introductionmentioning

confidence: 99%

Structural Dynamics of a Lytic Peptide Interacting with a Supported Lipid Bilayer

Rapson

Hossain

Wade

et al. 2011

Biophysical Journal

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The interaction of a melittin mutant with a 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC)-supported lipid bilayer was studied with the use of time-resolved evanescent wave-induced fluorescence spectroscopy (TREWIFS) and evanescent wave-induced time-resolved fluorescence anisotropy measurements (EW-TRAMs). The mutant peptide was labeled at position K14 with AlexaFluor 430 and retained the lytic activity characteristic of native melittin. The fluorescence decay kinetics of the conjugate was found to be biexponential with a short-lived component, τ(1), due to photoinduced electron transfer between AlexaFluor 430 and proximal side chains within or between the peptides. The longer-lived component, τ(2), was sensitive to the polarity of the microenvironment at or near the K14 position of the peptide. Upon interaction with a DPPC-supported bilayer, the proportional contribution of τ(1) increased, indicating a conformational change of the peptide. The values of τ(1) and τ(2) indicate that the AlexaFluor 430 probe experienced an environment with an equivalent polarity no less than that of methanol. EW-TRAMs data from the melittin mutant revealed hindered rotational motions of the AlexaFluor 430 probe both in the plane and perpendicular to the plane of the supported lipid bilayer. The data indicate a highly ordered and polar environment near the center of the melittin helix consistent with the formation of a toroidal pore.

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Section: Introductionmentioning

confidence: 99%

Structural Dynamics of a Lytic Peptide Interacting with a Supported Lipid Bilayer

Rapson

Hossain

Wade

et al. 2011

Biophysical Journal

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“…4,22 This design is especially useful for depth profiling experiments since the configuration leads to the excitation light entering and exiting the prism normal to the surface of the cylindrical face, regardless of the incidence angle relative to the interfacial region. This minimizes spurious reflections that may interfere with the measurement and causes minimal deviations (refraction) of the incident beam.…”

Section: Methodsmentioning

confidence: 99%

“…Upon TIR, a small amount of the light field penetrates the lower refractive index medium in the form of a standing wave known as an evanescent field. 4 The intensity profile within the evanescent field is related to the square of the E-field and decays exponentially with distance, z, from the interface, according to Equation 1:…”

Section: Introductionmentioning

confidence: 99%

“…TR-EWIF has been used to great effect by a number of authors, employing both time-and frequency domain methods on a variety of time-scales and on a range of experimental systems. 4,[6][7][8][9][10][11][12][13][14][15][16][17][18] Variable angle ("depth profiling") TR-EWIF can be further extended to evanescent wave-induced time-resolved fluorescence anisotropy measurements, EW-TRAM; a technique well suited to the study of fluorescence depolarizing processes whose dynamics occur on the nanosecond and sub-nanosecond time scales, such as chromophore/segmental motion, energy transfer and energy migration, etc.…”

Section: Introductionmentioning

confidence: 99%

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Time-resolved evanescent wave-induced fluorescence studies of macromolecular adsorption

2007

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Evanescent Wave (EW) fluorescence spectroscopic techniques are exploited to obtain information about the conformational state of macromolecules within close proximity of a solid/liquid interfacial region. Specifically, timeresolved evanescent wave-induced fluorescence techniques have been applied to the study of the adsorption of polymers and biomolecules to silica surfaces. We have extended these EW measurements using polarized excitation and emission detection to probe molecular motion and conformational change in the microenvironment of the interfacial region. We report on the observation of complex time-dependent fluorescence anisotropy data and the interpretation of these data in terms of in-and out-of-plane rotational motion. The macromolecular-interfacial systems investigated by this evanescent wave approach included polymer film dynamics and adsorbed protein rearrangement upon adsorption.

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“…After much effort over two decades, we came to the conclusion that modelling fluorescence decays obtained by mode-locked laser excitation and single-photon counting detection, while providing excellent results in terms of fitting to experimental decays, were unable definitively to distinguish between the various physical models upon which mathematical modelling was based. Some success was experienced, however, in observing polymers adsorbed on surfaces, using the technique of evanescent wave time-resolved fluorescence [20][21][22].…”

Section: Time-correlated Single-photon Countingmentioning

confidence: 99%

A lifetime in photochemistry; some ultrafast measurements on singlet states

Phillips¹

2016

Proc. R. Soc. A.

Self Cite

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We describe here the development of time-correlated single-photon counting techniques from the early use of spark discharge lamps as light sources through to the use of femtosecond mode-locked lasers through the personal work of the author. We used laser-excited fluorescence in studies on energy migration and rotational relaxation in synthetic polymer solutions, in biological probe molecules and in supersonic jet expansions. Time-correlated single-photon counting was the first method used in early fluorescence lifetime imaging microscopy (FLIM), and we outline the development of this powerful technique, with a comparison of techniques including wide-field microscopy. We employed these modern forms of FLIM to study single biological cells, and applied FLIM also to gain an understanding the distribution in tissue, and fates of photosensitizer molecules used in photodynamic therapy. We also describe the uses and instrumental design of laser systems for the study of ultrafast time-resolved vibrational spectroscopy.

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Time-resolved evanescent wave induced fluorescence spectroscopy. Part 1.—Deviations in the fluorescence lifetime of tetrasulphonated aluminium phthalocyanine at a fused silica/methanol interface

Cited by 28 publications

References 31 publications

Structural Dynamics of a Lytic Peptide Interacting with a Supported Lipid Bilayer

Structural Dynamics of a Lytic Peptide Interacting with a Supported Lipid Bilayer

Time-resolved evanescent wave-induced fluorescence studies of macromolecular adsorption

A lifetime in photochemistry; some ultrafast measurements on singlet states

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