Clinical Probes for ROS and Oxidative Stress

Quantum Sensing for Detection of Zinc‐Triggered Free Radicals in Endothelial Cells

“…[ 47 ] In general, high reactivity of DHE probes do not make them exclusive to superoxide detection only. [ 48 ] $$O_2^{ \bullet - }\;$$gets bound easily to many molecules, generating RNS, including peroxynitrite, or secondary ROS, such as hydrogen peroxide, hydroxyl radicals as well as alkoxy radicals. [ 49 ] One of the most challenging hurdles to overcome in the context of DHE‐based probes is the separation of 2‐hydroxyethidium, the adduct of $$O_2^{ \bullet - }$$ and DHE, from ethidium, an oxidation product of DHE.…”

“…[ 49 ] One of the most challenging hurdles to overcome in the context of DHE‐based probes is the separation of 2‐hydroxyethidium, the adduct of $$O_2^{ \bullet - }$$ and DHE, from ethidium, an oxidation product of DHE. [ 48 ] Thus, it has to be borne in mind that the probe is specific for a wide spectrum of ROS, particularly $$O_2^{ \bullet - }\;$$and H 2 O 2 . Any change in the concentration of superoxide and its derivates should be viewed as indicative of alterations in oxidative chemistry within the investigated environment, rather than solely representing the precise formation of superoxide.…”

“…What also needs to be clarified is that even though the DAF-FM assays are being widely employed to measure intracellular nitric oxide, they in fact provide information about nitrosation of the studied environment. [48,50] The actual mechanism governing the reactions of DAF-FM with NO • (or its oxidized adducts) to form benzotriazole inside cells remains a matter of debate. It may involve nitrosative (oxidation of NO • to yield N 2 O 3 ) and/or oxidative (one-electron oxidation of the reagent and subsequent reaction with nitric oxide) chemistry, which indicates that the probe might detect nitrosative reaction products of NO • , NO • itself, or both.…”

“…It may involve nitrosative (oxidation of NO • to yield N 2 O 3 ) and/or oxidative (one-electron oxidation of the reagent and subsequent reaction with nitric oxide) chemistry, which indicates that the probe might detect nitrosative reaction products of NO • , NO • itself, or both. [48,51] Diaminofluoresceins are unable to separate the NO • -specific fluorescent signals given off by the triazole derivates from nonspecific fluorescent products created by reaction of a probe with, e.g., other biomolecules within cells or reagents that modifies the steady-state concentration of the intermediate radicals. [51] Thereby, dealing with DAF-FM assays should be viewed as monitoring the integrated intensity of nitrosative chemistry in a specific bioenvironment rather than the exact formation of NO • .…”

Leucomethylene blue probe detects a broad spectrum of reactive oxygen and nitrogen species

“…Several strategies, methods and probes are employed currently for the detection of ROS and RNS. 2,8–10 Electron paramagnetic resonance (EPR) 11 and fluorescence-based techniques are prevalent, 12 followed by photometric, chemiluminescent and electrochemical methods. In all these techniques, the applied probes change their properties post-reaction (or trapping) with ROS/RNS, and enable the detection.…”