Peroxidase-induced degradation of single-walled carbon nanotubes: hypochlorite is a major oxidant capable ofin vivodegradation of carbon nanotubes

Abstract

Peroxidase-induced degradation of single-walled carbon nanotubes: hypochlorite is a major oxidant capable of in vivo degradation of carbon nanotubes -

Hypochlorite-induced structural modifications enhance the chaperone activity of human α2-macroglobulin

“…1B). Notably, dimeric α 2 M can be detected in blood plasma in the presence of micromolar to millimolar concentrations of NaOCl, which are predicted to be physiologically relevant based on in vitro and ex vivo studies (2,(31)(32)(33)(34). Diluting blood plasma with PBS (1:4 or 1:100) to give a final protein concentration similar to that of interstitial fluid or cerebral spinal fluid, respectively, results in greater amounts of the α 2 M dimers being liberated by the same concentration of NaOCl (Fig.…”

“…It is extremely difficult to measure directly the concentrations of hypochlorite generated by the myeloperoxidase-H 2 O 2 -chloride system in vivo; however, considering that 10 6 stimulated neutrophils can produce around 17 nmol hypochlorite in vitro (47) and at sites of inflammation, neutrophil numbers may exceed 5 × 10 4 cells/mm 3 (48), it is feasible that physiological hypochlorite concentrations reach high-micromolar or low-millimolar levels in inflamed tissues (2,31). Consistent with the idea that a large amount of hypochlorite may be generated in vivo during inflammation, extracellular myeloperoxidase is also estimated to reach millimolar concentrations (33), and using computational modeling, it is predicted that proteins from atherosclerotic plaques are exposed to a 20-fold molar excess of hypochlorite over their lifetime (32).…”

Redox‐enzymes, cells and micro‐organisms acting on carbon nanostructures transformation: A mini‐review

“…Apparently, the destruction of the enzyme active site in the presence of H 2 O 2 in a free radical formation‐mediated Fenton‐like reaction could account for a peroxidase‐induced degradation of the nanotube. Moreover, by comparing the ability of peroxidases to degrade carbon nanotubes, MPO (which is capable of generating hypochlorite) and LPO (which produces hypobromite) were found to be efficient in the degradation of carbon nanotubes 42…”

“…For instance, by considering just the surface charge, it was observed that SWCNTs with a negatively‐charged surface have a more readily uptake by macrophages,83 in comparison to nonfunctionalized SWCNTs, which are poorly recognized and did not induce common activation responses (e.g., superoxide and nitric oxide production) 84. Furthermore, oxygenated surface functionalities in the sp2 graphitic structure had a substantial influence on the biodegradation of these materials by enzymes, cell or micro‐organisms 39, 41–46, 50–52, 55, 57. In a more detailed analysis, the surface microchemical environment of oxidized carbon nanotubes and graphenes comprises a myriad of oxygenated structures based on groups such as alcohols, ketones, ethers, esters, carboxylic acids, and anhydrides,85, 86 and other shorter oxidized fragments, which are strongly adsorbed on the graphitic sheets 87, 88.…”

Payload drug vs. nanocarrier biodegradation by myeloperoxidase- and peroxynitrite-mediated oxidations: pharmacokinetic implications

“…S12 and S13) demonstrate that the nanocarrier was subject to structural transformation, where peroxynitrite (ONOO − ) can promote (1) direct nucleophilic reactions and (2) one- or two-electron transfer oxidations. 32 …”