Table 9. Small-Molecule Toxic Metal Probes.
| excitation |
emission |
brightnessb |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| sensor | λfree (nm) | εfreea | λbound (nm) | εbounda | λfree (nm) | φfree | λbound (nm) | φbound | free | bound | DRc | KD (M) | ref |
| Lead (Pb2+) | |||||||||||||
| LF1 | 490 | 25.0 | 490 | 28.0 | 514 | 0.001 | 514 | 0.013 | 0.03 | 0.36 | 18 | 2.3 × 10–7 | (231) |
| Leamium | 490 | 520 | |||||||||||
| Cadmium (Cd2+) | |||||||||||||
| Liu Cd-1 | 503 | 80.0 | 503 | 80.0 | 518 | 0.006 | 518 | ND | 0.48 | ND | 2 | 8.1 × 10–6 | (232) |
| Peng Cd-1 | 600 | ND | 571 | ND | 656 | 0.12 | 597 | 0.59 | ND | ND | ND | 5–7 × 10–5 | (233) |
| Cheng Cd-1 | 550 | ND | 550 | ND | 578 | 0.003 | 578 | 0.3 | ND | ND | 195 | 6.0 × 10–7 | (234) |
| Mameli Cd-L | 332 | 37.0 | 332 | ND | 510 | 0.0001 | 510 | ND | ND | ND | 13 | 1.0 × 10–6 | (235) |
| DBITA | 362 | ND | 362 | ND | 493/534 | 0.18 | 493/587 | 0.42 | ND | ND | 3 | 2.5 × 10–13 | (236) |
| DQCd1 | 405 | ND | 405 | ND | 558 | 0.15 | 495 | 0.11 | ND | ND | 15 | 4.1 × 10–13 | (237) |
| CYP-1 | 766 | 158.0 | 766 | 156.0 | 791 | 0.0012 | 791 | 0.035 | 0.19 | 5.46 | ND | 4.4 × 10–7 | (238) |
| CYP-2 | 771 | 152.0 | 771 | 147.0 | 793 | 0.0059 | 793 | 0.015 | 0.90 | 2.21 | ND | 5.0 × 10–6 | (238) |
| Mercury (Hg2+) | |||||||||||||
| 8H-BDP | 470 | ND | 470 | ND | 509 | 0.002 | 509 | ND | ND | ND | 27 | 6.3 × 10–19 | (239) |
| MF1 | 485 | 20.0 | 495 | 49.0 | 514 | 0.001 | 517 | 0.16 | 0.02 | 7.84 | 170 | 7.0 × 10–11 | (240) |
| Hatai Hg-1 | 340 | ND | 340 | ND | 590 | 0.022 | 540 | 0.4 | ND | ND | 19 | 8.0 × 10–7 | (241) |
| Zhao Hg-1 | 530 | ND | 530 | ND | 586 | ND | 586 | ND | ND | ND | 1200 | 4.6 × 10–7 | (242) |
| RG1 | 500 | ND | 500 | ND | 550 | ND | 550 | 0.48 | ND | ND | ND | 2.0 × 10–6 | (243) |
| Lin Hg-1 | 500 | ND | 500 | ND | 561 | ND | 561 | ND | ND | ND | 1000 | 2.5 × 10–5 | (244) |
| RS1 | 500 | ND | 500 | ND | 564 | ND | 564 | ND | ND | ND | 120 | 1.9 × 10–6 | (245) |
| reaction-based Hg2+ probes | λ-unreacted (nm) | ε-unreacted | λ-reacted (nm) | ε-reacted | λ-unreacted (nm) | Φ-unreacted | λ-reacted (nm) | Φ-reacted | unreacted | reacted | DRc | detection limit (M) | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| RBPH | 530 | ND | 530 | ND | 630 | ND | 580 | 0.61 | ND | ND | ND | 1.9 × 10–7 | (246) |
| RBC1 | 365 | ND | 365 | ND | 468/590 | 0.31/ND | 590 | ND/0.13 | ND | ND | 240 | 2.1 × 10–9 | (247) |
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 (DR), so we encourage readers to refer to the original publications for more details about this value. For intensity-based probes, this number is generally the maximum fold change in fluorescence intensity upon metal ion binding. ND, not determined.