Rearranging Spin Electrons by Axial-Ligand-Induced Orbital Splitting to Regulate Enzymatic Activity of Single-Atom Nanozyme with Destructive d-π Conjugation

J Am Chem Soc. 2024 May 29;146(21):14875-14888. doi: 10.1021/jacs.4c04322. Epub 2024 May 15.

Abstract

Most of the nanozymes have been obtained based on trial and error, for which the application is usually compromised by enzymatic activity regulation due to a vague catalytic mechanism. Herein, a hollow axial Mo-Pt single-atom nanozyme (H-MoN5@PtN4/C) is constructed by a two-tier template capture strategy. The axial ligand can induce Mo 4d orbital splitting, leading to a rearrangement of spin electrons (↑ ↑ → ↑↓) to regulate enzymatic activity. This creates catalase-like activity and enhances oxidase-like activity to catalyze cascade enzymatic reactions (H2O2 → O2 → O2•-), which can overcome tumor hypoxia and accumulate cytotoxic superoxide radicals (O2•-). Significantly, H-MoN5@PtN4/C displays destructive d-π conjugation between the metal and substrate to attenuate the restriction of orbitals and electrons. This markedly improves enzymatic performance (catalase-like and oxidase-like activity) of a Mo single atom and peroxidase-like properties of a Pt single atom. Furthermore, the H-MoN5@PtN4/C can deplete overexpressed glutathione (GSH) through a redox reaction, which can avoid consumption of ROS (O2•- and OH). As a result, H-MoN5@PtN4/C can overcome limitations of a complex tumor microenvironment (TME) for tumor-specific therapy based on TME-activated catalytic activity.

MeSH terms

  • Catalase / chemistry
  • Catalase / metabolism
  • Catalysis
  • Electrons*
  • Glutathione / chemistry
  • Glutathione / metabolism
  • Humans
  • Hydrogen Peroxide / chemistry
  • Hydrogen Peroxide / metabolism
  • Ligands
  • Nanostructures / chemistry
  • Platinum / chemistry

Substances

  • Ligands
  • Platinum
  • Catalase
  • Hydrogen Peroxide
  • Glutathione