Effect of dissociation constant (pKa) of natural organic matter on photo-generation of reactive oxygen species (ROS)

Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2020

“…The indirect pathway for the photolysis of POPs is particularly relevant, since some of these contaminants (e.g., perfluorinated octanoic acid (PFOA) and some pesticides) do not absorb significantly within the UV region of the solar spectrum and therefore undergo direct photoreaction very slowly. In natural waters, they may be potentially transformed/degraded via indirect photolysis mediated by natural sensitisers (e.g., DOM, nitrate or nitrite) that absorb solar radiation to form photochemically produced reactive intermediates [ 329 , 334 , 348 , 349 ].…”

A multi-responsive Au NCs@PMLE/Ca2+ antitumor hydrogel formed in situ on the interior/surface of tumors for PT imaging-guided synergistic PTT/O2-enhanced PDT effects

“…The reason might be that the catalase in PMLE catalyzed H 2 O 2 decomposition in TME to produce O 2 ; meanwhile, the endogenous photosensitizers of chlorophyll in PMLE could effectively absorb light, drive the electrons of O 2 , transferring from the ground state to the excited state, and produce 1 O 2 . 48 In the previous article, 49 the HOMO–LUMO gap of Au NCS was approximately 1.9 eV, which was larger than the activation energy (Δ E ) of the O 2 molecule ( 3 O 2 → 1 O 2 , Δ E = 0.97 eV), resulting in 1 O 2 photogeneration. In Fig.…”

CuO Nanoparticles as Copper-Ion Reservoirs for Elesclomol-Mediated Intracellular Oxidative Stress: Implications for Anticancer Therapies

“…The dissolution of CuO nanoparticles, therefore, provides a constant supply of Cu (II) ions for a longer duration to Elesclomol and hence makes it a better candidate for inducing prolonged oxidative stress. According to Du et al (2020), 25 there is a positive correlation between the ROS production with that of dissociation constant (pK a ) of an organic compound. The reported theoretically calculated pK a value of 11.41 for the Elesclomol−Cu(II) complex is considered to be higher in the reducing environment like mitochondria.…”