Table 20.1 Molecular Probes pH indicator families, in order of decreasing pKa.
| Parent Fluorophore | pH Range | Typical Measurement |
|---|---|---|
| SNARF indicators | 6.0–8.0 | Emission ratio 580/640 nm |
| HPTS (pyranine) | 7.0–8.0 | Excitation ratio 450/405 nm |
| BCECF | 6.5–7.5 | Excitation ratio 490/440 nm |
| Fluoresceins and carboxyfluoresceins | 6.0–7.2 | Excitation ratio 490/450 nm |
| LysoSensor Green DND-189 | 4.5–6.0 | Single emission 520 nm |
| Oregon Green dyes | 4.2–5.7 | Excitation ratio 510/450 nm or excitation ratio 490/440 nm |
| LysoSensor Yellow/Blue DND-160 | 3.5–6.0 | Emission ratio 450/510 nm |
| pHrodo dye | see below * | Single emission 585 nm |
| * pHrodo succinimidyl ester exhibits a complex pH titration profile. Decreasing pH (from pH 9 to pH 2) produces a continuous (but nonlinear) fluorescence increase. This pH response profile typically changes upon conjugation of the dye to proteins and other biomolecules. | ||
For Research Use Only. Not for use in diagnostic procedures.