| molecular probes |
<1 |
– to + |
A, F |
commercial availability,
no further modifications, cover a wide spectral range |
undefined properties in
complex biological environment |
| genetically encoded fluorescent
proteins |
∼3 |
– to ∼ |
F |
biocompatible; can be used
for intra- and extracellular measurements |
long maturation times for
some proteins |
| dendrimers |
1–14 |
– to + |
A, F |
lower interferences compared
to molecular probes |
only partial protection
from environment; high synthetic effort |
| quantum dots of type MeX |
2–10 |
+ |
F |
high brightness; often relatively
long luminescence decay times and FLIM suitability |
blinking; toxicity |
| upconversion nanomaterials |
10–100 |
+ |
F |
complete elimination of
background fluorescence |
2-wavelength ratiometry
often possible; typically photoexcited at 880 or 980 nm |
| organic polymeric NPs |
10–200 |
– to + |
A, F |
high versatility in materials,
preparation methods, cell penetrating properties and size |
robust methods for indicator
immobilization are necessary to avoid leaching resulting in higher
effort |
| silica NPs |
3–200 |
– to + |
A, F |
high versatility in materials,
preparation methods, cell penetrating properties and size |
robust methods for indicator
immobilization are necessary to avoid leaching resulting in higher
effort |
| carbonaceous nanomaterials |
3–15 |
+ |
F |
simple preparation |
mostly short-wavelength
excitation; emission can depend on exc. wavelength, prone to interferences |
| polymeric micelles
with
conformational changes |
3–50 |
– to + |
A, F |
also pH-insensitive dyes
can be used |
very
narrow dynamic range;
concentration dependence of micellar formation except for unimolecular
micelles |
