New progress in spectroscopic probes for reactive oxygen species

Imaging HOCl Generation during the Mitochondria Peripheral Fission with a Tailor-Made Fluorescent Probe

“…As shown in Figure 1E, the tested ROS even at a much higher concentration do not produce obvious fluorescence enhancement except HOCl; moreover, ONOO − does not cause a significant increase in fluorescence. This high selectivity of the probe can be attributed to the specific oxidative cleavage of the C�N double bond (the recognition moiety) 21 in the dibenzo [1,4]oxazepine core by HOCl. In addition, potential coexisting inorganic salts and biological active species, such as glutathione, amino acids, and glucose, hardly generate fluorescence (Figure 1F), also demonstrating the high selectivity of ON-mito for HOCl.…”

“…Among the various kinds of ROS, hypochlorous acid (HOCl), endogenously generated from the reaction of H 2 O 2 and chloride ions in the presence of myeloperoxidase, possesses strong oxidization and has been found to promote cell apoptosis by influencing mitochondrial osmotic transport pore and apoptotic signaling molecule. − Nevertheless, the changing behavior of HOCl during the mitochondrial peripheral fission remains unclear. Fluorescent probes have been extensively used for cellular and subcellular imaging, − but none of them are suitable for detecting mitochondrial HOCl because of about 0.8-fold decreased pH during the peripheral fission; in other words, the HOCl probe must be nonfluorescent at pH 8 (normal mitochondrial pH) but highly fluorescent at pH 6.4 (peripheral fission pH). The stringent requirement, however, is a great challenge for probe design.…”

Recent Advances of Fluorescence Probes for Imaging of Ferroptosis Process

“…H2O2 is a relative stable and mild ROS. Boronate ester is one of the most commonly used recognition group for H2O2 [56,57]. In response to H2O2, aromatic boronate ester can be oxidized to its corresponding phenol product, which usually results in the fluorescence of the connected fluorophore increase or alteration.…”

“…HP has been used to image the change in intracellular H2O2 level regulated by the H2O2 inducer or activator, and visualize the significant H2O2 release in HepG2 cells incubated with ferroptosis inducer erastin for 12 h, revealing it as a feature of ferroptosis process. [56,57]. In response to H 2 O 2 , aromatic boronate ester can be oxidized to its corresponding phenol product, which usually results in the fluorescence of the connected fluorophore increase or alteration.…”

Rational design of an iminocoumarin‐based fluorescence probe for peroxynitrite with high signal‐to‐noise ratio

“…Compared with conventional detection methods, fluorescence imaging technology is considered a potentially powerful method for visualizing ONOO À in biological processes due to its excellent temporal and spatial resolution [7][8][9]. Theoretically, a fluorescent probe is typically composed of a recognition unit and a fluorophore [10][11][12][13][14][15][16]. The recognition unit can conduct selective interactions or chemical reactions with the targeted substance, while the fluorophore is responsible for reporting the changes in its fluorescence signals.…”