Biomedical Engineering Reference
In-Depth Information
Figure 42.10.
Fluorescent probes for detection of superoxide. (a) Cydro-
cyanine and (b)PNF-1.
mechanistic details and precise roles in pathology, aging, and
diseases in living organisms. However, it is challenging to detect
superoxide quantitatively because ofits extremely short half-life.
Recently, a new class of fluorescent sensors has been developed
that can image superoxide and hydroxyl radicals in cell cultures,
tissue, and
in vivo
(Fig. 42.10a).
29
The fluorescent sensors were
termed hydrocyanines, which were synthesized in one step from
the commercially available cyanine dyes. Hydrocyanines are weakly
fluorescentbecauseofdisrupted
π
-conjugations.However,afteroxi-
dation with either superoxide or hydroxyl radicals they exhibit dra-
matically increased fluorescence by regenerating their extended
π
-conjugations. Hydrocyanines have physicochemical properties
needed for the detection of intracellular ROS. They are initially
noncharged and membrane permeable. However, oxidation with
either superoxide or hydroxyl radicals converts them into charged
and membrane-impermeable molecules, which can accumulate in
ROS-overexpressing cells. They have excellent stability, nanomolar
sensitivity, and specificity to ROS. Furthermore, they were capable
of imaging superoxide and hydroxy radical in cell cultures, tissue
explants, andLPS-treated mice.
Search WWH ::
Custom Search