Table 5. Small-Molecule Sensors for Cu+.
| excitation |
emission |
brightnessb |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| sensor | λfree (nm) | εfreea | λbound (nm) | εbounda | λfree (nm) | φfree | λbound (nm) | φbound | free | bound | DRc | KD (M) | ref |
| CTAP-1 | 365 | ND | 365 | 480 | 0.003 | 480 | 0.14 | ND | ND | 4.6 | 4.00 × 10–8 | (167) | |
| CS1 | 540 | 30.0 | 540 | 40.0 | 566 | 0.016 | 561 | 0.13 | 0.48 | 5.20 | 10 | 3.60 × 10–12 | (168) |
| CS3 | 550 | 31.0 | 540 | 46.0 | 560 | 0.007 | 548 | 0.4 | 0.22 | 18.40 | 75 | 8.90 × 10–14 | (169) |
| RCS1 | 480 | 43.0 | 548 | 40.0 | 505, 570 | 0.002, 0.003 | 556 | 0.002, 0.05 | 0.13 | 2.00 | 20 | 4.00 × 10–11 | (170) |
| Mito-CS1 | 555 | 28.0 | 550 | 26.0 | 569 | 0.009 | 558 | 0.05 | 0.25 | 1.30 | 10 | 7.20 × 10–12 | (67c) |
| ACu1 | 359 | ND | 363 (750)* | ND | 492 | 0.028 | 482 | 0.13 | ND | ND | 4 | 2.00 × 10–11 | (171) |
| CS790 | 760 | ND | 760 | ND | 790 | 0.0042 | 790 | 0.072 | ND | ND | 15 | 3.00 × 10–11 | (172) |
| CTAP-2 | ND | ND | 396 | 29.0 | ND | ND | 508 | 0.083 | ND | 2.41 | 65 | 4.00 × 10–12 | (71) |
| Cao Cu-3 | 696 | ND | 750 | ND | 792 | ND | ND | ND | ND | ND | 9.6 | 6.10 × 10–12 | (173) |
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 Cu+ binding. ND, not determined.