On the Possibility of Long-Wavelength Long-Lifetime High-Quantum-Yield Luminophores

Abstract

We describe an approach to creating a new class of luminophores which display both long wavelength emissions exceeding 600 nm and long lifetimes. These luminophores are based on resonance energy transfer (RET) from a long lifetime donor to a short lifetime but long wavelength acceptor. We demonstrated the possibility of obtaining these desirable spectral properties using donors and acceptors noncovalently bound to DNA. The donor was a ruthenium (Ru) metal-ligand complex in which one of the diimine ligands intercalated into double-helix DNA. The acceptors were either nile blue, TOTO-3, or TO-PRO-3. Upon binding of the acceptor to donor-labeled DNA, we found that the acceptor quantum yield was remarkably enhanced so that the wavelength-integrated intensities of the donor and acceptor bound to DNA were many-fold greater than the intensity of the donor and acceptor alone when separately bound to DNA. The origin of this effect is efficient energy transfer from the donor. Under these conditions the effective overall quantum yield approaches that of the acceptor. Importantly, the increased quantum yield can be obtained while maintaining usefully long apparent acceptor lifetimes of 30 to 80 ns. The effect of an increased quantum yield from a low quantum yield donor may find use in assays to detect macromolecular binding interactions. These results suggest the synthesis of covalently linked donor-acceptor pairs with the desirable spectral properties of long wavelength emission, high quantum yield, and moderately long lifetimes for gated detection.

Dopamine 5 receptor mediates Ang II type 1 receptor degradation via a ubiquitin-proteasome pathway in mice and human cells

“…In this study, we used image e (donor excitation in donor channel of double-labeled specimen) as the reference image for selection of ROIs to separate plasma membrane and cytoplasm fluorescence. The percentage of energy transfer (E%) images was processed on a pixel-by-pixel basis by using the equation E% = 1 -{Ida/(Ida + pFRET × [Pd/Pa] × [Sd/Sa] × [Qd/Qa])}; where Pd and Pa (photo multiplier tube gain of donor and acceptor channels, respectively) set to the same when images were acquired; Sd and Sa (spectral sensitivity of donor and acceptor channels, respectively) were provided by the manufacturer; Qd and Qa (donor and acceptor quantum yield, respectively) were measured by spectrofluorometer as described previously (57); Ida is the image of donor excitation in donor channel of double labeling samples after removing of background; and pFRET is the processed or corrected FRET. The calculation of distance of donor and acceptor (r) was based on the following previously described equation (33): r = R0{(1/E)−1} 1/6 , where E is the efficiency of energy transfer.…”

Energy Transfer from Ethidium to Cationic Porphyrins Mediated by DNA and Synthetic Polynucleotides at Low Binding Densities

“…In the excited state, charge separation between the fluorophore and the quencher has been suggested. 40 This observation contrasted with results from TMPyP. Neglecting the contribution from the dynamic mechanism, at least two static mechanisms could be involved in the TMPyP quenching.…”

Dynamics of Supercoiled and Linear pBluescript II SK(+) Phagemids Probed with a Long-lifetime Metal-ligand Complex

“…The phen derivative RuPD has some advantages over the other bpy derivative RuBD. The lifetimes of RuBD bound to DNA are about 100 ns (Jenkins et al, 1992;Murphy and Barton, 1993;Lakowicz et al, 1995Lakowicz et al, , 2001Malak et al, 1997;Kang et al, 2002a,b). RuPD showed still longer lifetimes bound to DNA, with a mean decay time near 500 ns (Table 1).…”