Select characteristics of representative multi-FRET linear photonic wires.
| DNA structure (estimated length) | # of ET steps | Fluorophores/D → A | r DA a | E ee | Notes | Ref. |
|---|---|---|---|---|---|---|
| 25 bp ds triplex (∼8 nm) | 2 | 3/6-Carboxy Fl, hexachloro-6-carboxy FL, 6-carboxy-X-rhodamine | — | ∼16% | Relay dye increases Eee from 10% to 16% | 239 |
| 30 & 40 bp ds duplex (∼8 nm) | 3 (+ 1 homoFRET) | 3/Eosin, TAMRA, Texas Red | 10 bp < 1 × R0 for each D–A pair | 20% | 10 bp (1 helix) separates dyes. Eee increase 8% to 20% for 2xTAMRA relay on 40 bp | 240 |
| 60 bp ds duplex (∼13.6 nm) | 4 | 5/RhG, TAMRA, Atto 590, LCR, Atto 680 | 10 bp < 1 × R0 for each D–A pair | 15–30% | smFRET shows subpopulations with 90% Eee | 231 |
| ds concatenated duplex (>15 nm) attached to QD | 4 | 5/525 nm QD, Cy3, Cy3.5, Cy5, Cy5.5, | 0.5, 1.0, 1.5 × R0 for each D–A pair | 10% | Multiple DNA wires arrayed around QD increases EFRET QD:(DNA)8 | 241 |
| 86 bp ds concatenated duplex (∼29 nm) | 6 | 7/Fl, Cy3, Cy3.5, AF610, Cy5, Cy5.5, AF700 | 0.3–0.5 × R0 for each D–A pair | ∼5% for 1st 5 ET steps | AF610 acts as energy sink AF700 acts as dark quencher | 242 |
| ds concatenated duplex (>14 nm) attached to QD | 5 | 6/Luc, 540 nm QD, Cy3, Cy3.5, AF647, Cy5.5 | 0.5–0.7 × R0 for each D–A pair | 10% | Luc → QD BRET. Construct = (Luc)6:QD:(DNA)8 | 243 |
a
r DA D–A separation distance given as a function of R0 for the D–A pairs, → = ET step, – not given, AF-AlexaFluor, BRET-bioluminescence resonance energy transfer, Fl-fluorescein, LCR-LightCycler Red, Luc-luciferase enzyme, RhG-rhodamine green, TAMRA-tetramethylrhodamine, smFRET-single molecule FRET, 525 nm QD/540 nm QD-quantum dot with 525 nm/540 nm emission maxima.