Ultrafast Dynamics of Fluorescent DNA Intercalators

Fürstenberg, Alexandre; Julliard, Marc D.; Deligeorgiev, Todor; Gadjev, Nikolai; Vassilev, Aleksey; Vauthey, Eric

doi:10.1016/b978-044452821-6/50056-3

Cited by 2 publications

(2 citation statements)

References 13 publications

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“…We have recently shown that the fluorescence enhancement of YOYO derivatives upon DNA binding is only partially due to this mechanism. − Indeed, when free in water, these homodimeric dyes tend to form intramolecular H-type dimers. As a result of a strong excitonic interaction within these aggregates, the radiative transition from the lowest electronic excited state is characterized by a very small oscillator strength, and thus self-aggregated H-dimers are essentially nonfluorescent.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast Excited-State Dynamics of Oxazole Yellow DNA Intercalators

Fürstenberg

Vauthey

2007

J. Phys. Chem. B

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The excited-state dynamics of the DNA intercalator YO-PRO-1 and of three derivatives has been investigated in water and in DNA using ultrafast fluorescence spectroscopy. In the free form, the singly charged dyes exist both as monomers and as H-dimers, while the doubly charged dyes exist predominantly as monomers. Both forms are very weakly fluorescent: the monomers because of ultrafast nonradiative deactivation, with a time constant on the order of 3-4 ps, associated with large amplitude motion around the methine bridge, and the H-dimers because of excitonic interaction. Upon intercalation into DNA, large amplitude motion is inhibited, H-dimers are disrupted, and the molecules become highly fluorescent. The early fluorescence dynamics of these dyes in DNA exhibits substantial differences compared with that measured with their homodimeric YOYO analogues, which are ascribed to dissimilarities in their local environment. Finally, the decay of the fluorescence polarization anisotropy reveals ultrafast hopping of the excitation energy between the intercalated dyes. In one case, a marked change of the depolarization dynamics upon increasing the dye concentration is observed and explained in terms of a different binding mode.

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Section: Introductionmentioning

confidence: 99%

Ultrafast Excited-State Dynamics of Oxazole Yellow DNA Intercalators

Fürstenberg

Vauthey

2007

J. Phys. Chem. B

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“…Driven by previous results which suggested that free homodimeric dyes that aggregate have an enhanced, although very low, fluorescence quantum yield with respect to dyes that do not aggregate, [41] we have therefore investigated a series of monomeric (YO) and homodimeric (YOYO) derivatives of oxazole yellow by time-resolved fluorescence and steady-state absorption and fluorescence spectroscopies. [41,43] We will show below that aggregation also operates at low concentration with the monomeric dyes, that this process is controlled mainly by the charge and the nature of the substituents of the dyes, and that maximum contrast between free and bound forms would be reached with dyes for which aggregation can be minimised and isomerisation is the fastest.…”

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confidence: 99%

Structure–Fluorescence Contrast Relationship in Cyanine DNA Intercalators: Toward Rational Dye Design

Fürstenberg

Deligeorgiev

Gadjev

et al. 2007

Chemistry A European J

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The fluorescence enhancement mechanisms of a series of DNA stains of the oxazole yellow (YO) family have been investigated in detail using steady‐state and ultrafast time‐resolved fluorescence spectroscopy. The strong increase in the fluorescence quantum yield of these dyes upon DNA binding is shown to originate from the inhibition of two distinct processes: 1) isomerisation through large‐amplitude motion that non‐radiatively deactivates the excited state within a few picoseconds and 2) formation of weakly emitting H‐dimers. As the H‐dimers are not totally non‐fluorescent, their formation is less efficient than isomerisation as a fluorescent contrast mechanism. The propensity of the dyes to form H‐dimers and thus to reduce their fluorescence contrast upon DNA binding is shown to depend on several of their structural parameters, such as their monomeric (YO) or homodimeric (YOYO) nature, their substitution and their electric charge. Moreover, these parameters also have a substantial influence on the affinity of the dyes for DNA and on the ensuing sensitivity for DNA detection. The results give new insight into the development and optimisation of fluorescent DNA probes with the highest contrast.

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Ultrafast Dynamics of Fluorescent DNA Intercalators

Cited by 2 publications

References 13 publications

Ultrafast Excited-State Dynamics of Oxazole Yellow DNA Intercalators

Ultrafast Excited-State Dynamics of Oxazole Yellow DNA Intercalators

Structure–Fluorescence Contrast Relationship in Cyanine DNA Intercalators: Toward Rational Dye Design

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