Table 7. Fluorescent Probes for Fe2+ and Fe3+.
| excitation |
emission |
brightnessb |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| name | λfree (nm) | εfreea | λbound (nm) | εbounda | λfree (nm) | φfree | λbound (nm) | φbound | free | bound | KD (M) | DRc | ref |
| calcein | 486 | ND | 486 | ND | 517 | ND | 517 | ND | ND | ND | 2.2 × 10–7 | 43% | (191) |
| Phen Green SK | 507 | ND | 507 | ND | 532 | ND | 532 | ND | ND | ND | ND | 96% | (192) |
| RhoNox-1 | 492 | 24 | 555 | ND | 575 | 0.01 | 575 | 0.3 | ND | ND | ND | 30 | (193) |
| BDP-Cy-Tpy | 485 | ND | 485 | ND | 507 | ND | 507 | ND | ND | ND | 2.5 × 10–6 | ND | (194) |
| 569 | ND | 596 | ND | 635 | ND | 635 | ND | ND | ND | ||||
| AGD | 430 | 5.2 | 430 | ND | 480 | 0.103 | 480 | 0.0057 | ND | ND | 2.4 × 10–5 | 33% | (195) |
| IP1 | 470 | 0.4 | 470 | 0.4 | 508 | ND | 508 | ND | ND | ND | ND | ND | (196) |
| OuYang Fe-1 | 520 | ND | 520 | ND | 561 | ND | 583 | 0.13 | ND | ND | ND | 1000 | (197) |
| NBD-DFO | 475 | 7 | 475 | ND | 548 | 0.79 | 548 | ND | ND | ND | ND | ND | (198) |
| SF34 | 491 | 49.6 | 491 | ND | 514 | ND | 514 | ND | ND | ND | ND | 77% | (199) |
| Pyochelin-1 | 470 | ND | 470 | ND | 545 | 6 | 545 | 0.5 | ND | ND | 1.6 × 10–11 | 290 | (200) |
| Pyochelin-2 | 470 | ND | 470 | ND | 545 | ND | 545 | ND | ND | ND | 3.8 × 10–20 | 320 | (200) |
| RNP1 | 371 | ND | 371 | ND | 431 | 0.004 | 594 | 0.14 | ND | ND | 5 × 10–5 | ND | (201) |
a
Molar extinction coefficients given as ε/103 M–1 cm–1.
b
Brightness is defined as the product of the molar extinction coefficient and the quantum yield (ε × φ).
c
There is no systematic way to present dynamic range, so we encourage readers to refer to the original publications for more details about this value. For turn-on probes, this number is generally the maximum fold change in fluorescence intensity upon Fe2+/Fe3+ binding. For turn-off probes, this is the % quenching of maximal signal upon Fe2+/Fe3+ binding. ND, not determined.