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Oxidase-like manganese oxide nanoparticles: a mechanism of organic acids/aldehydes as electron acceptors and potential application in cancer therapy.

Yang PanZhuangzhuang ZhangJu-E CunXi FanQingqing PanWen-Xia GaoQiang LuoBin HeYuji Pu
Published in: Nanoscale (2024)
Identifying the underlying catalytic mechanisms of synthetic nanocatalysts or nanozymes is important in directing their design and applications. Herein, we revisited the oxidation process of 4,4'-diamino-3,3',5,5'-tetramethylbiphenyl (TMB) by Mn 3 O 4 nanoparticles and revealed that it adopted an organic acid/aldehyde-triggered catalytic mechanism at a weakly acidic or neutral pH, which is O 2 -independent and inhibited by the pre-addition of H 2 O 2 . Importantly, similar organic acid/aldehyde-mediated oxidation was applied to other substrates of peroxidase in the presence of nanoparticulate or commercially available MnO 2 and Mn 2 O 3 but not MnO. The selective oxidation of TMB by Mn 3 O 4 over MnO was further supported by density functional theory calculations. Moreover, Mn 3 O 4 nanoparticles enabled the oxidation of indole 3-acetic acid, a substrate that can generate cytotoxic singlet oxygen upon single-electron transfer oxidation, displaying potential in nanocatalytic tumor therapy. Overall, we revealed a general catalytic mechanism of manganese oxides towards the oxidation of peroxidase substrates, which could boost the design and various applications of these manganese-based nanoparticles.
Keyphrases
  • electron transfer
  • hydrogen peroxide
  • density functional theory
  • oxide nanoparticles
  • cancer therapy
  • room temperature
  • molecular dynamics
  • nitric oxide
  • stem cells
  • single cell
  • water soluble
  • climate change
  • amino acid