Table 9. Overview of Nanosensors Based on Quantum Dotsa.
| material | sensing mechanism | comments | ref |
|---|---|---|---|
| CdSe/ZnS | deprotonation of COOH groups on the surface | decay time sensing (τ = 8.7–15.5 ns) | (801) |
| Cu-doped CdZnS | deprotonation of COOH groups on the surface | tunable emission, decay time sensing (τ = 200–900 ns) | (798) |
| CdSe/ZnS | deprotonation of COOH groups on the surface | intensity measurement, pH range 4–12, smartphone-based read-out | (812) |
| CdSe/ZnS | quenching via hole transfer to phenol, no quenching for phenolate | intensity measurement, decay time measurement (τ = 0.65–4.86 ns) | (804) |
| CdSe/ZnS | quenching via hole transfer to amine, no quenching for protonated amine | intensity measurement, decay time measurement (τ = 12.32–33.74 ns) | (805) |
| CdSe/ZnS | pH-dependent quenching from oxidized dopamine | ratiometric 2–λ sensing | (813) |
| CdSe/ZnS + squaraine | FRET from QD to the pH indicator | ratiometric 2−λ sensing | (806) |
| CdSe/CdZnS + SNARF | FRET from QD to the pH indicator | ratiometric 2−λ sensing, identical pH response under two-photon excitation | (807) |
| CdSe/ZnS + pyrene | FRET from pyrene to QD; polymeric linker undergoes swelling upon protonation | ratiometric 2−λ sensing | (807) |
| CdSe/CdZnS + fluorescein | FRET from pH indicator to QD | ratiometric 2−λ sensing | (811) |
| CdZnSe/CdZnS/ZnS + fluorescein | FRET from QD to the pH indicator | ratiometric 2−λ sensing | (814) |
| CdSe/ZnSe + naphthofluorescein | FRET from QD to the pH indicator | ratiometric 2−λ sensing | (815) |
| CdTeSe/ZnS + cyanine dye | FRET from QD to the pH indicator | decay time sensing (τ = 12–29 ns) | (808) |
| mercaptoacetic acid capped CdSe/ZnSe/ZnS | deprotonation of COOH groups on the surface | intensity measurement, loss of surface capping at low pH, resulting in aggregation | (816) |
| QD ITK + mOrangeb | FRET from QD to pH sensitive GEFP | ratiometric 2−λ sensing | (660) |
| black phosphorus QDs | protonation and deprotonation of hydroxyl groups causes a different degree of quenching | particle size 5.2 nm; pH range of 1.0–9.0 | (817) |
a
A more detailed version of the table can be found in the Table S8.
b
Commercially available QDs.