Understanding the antibacterial mechanism of CuO nanoparticles: revealing the route of induced oxidative stress

Small. 2012 Nov 5;8(21):3326-37. doi: 10.1002/smll.201200772. Epub 2012 Aug 13.


To date, there is still a lack of definite knowledge regarding the interaction of CuO nanoparticles with bacteria and the possible permeation of the nanoparticles into bacterial cells. This study was aimed at shedding light on the size-dependent (from the microscale down to the small nanoscale) antibacterial activity of CuO. The potent antibacterial activity of CuO nanoparticles was found to be due to ROS-generation by the nanoparticles attached to the bacterial cells, which in turn provoked an enhancement of the intracellular oxidative stress. This paradigm was confirmed by several assays such as lipid peroxidation and reporter strains of oxidative stress. Furthermore, electron microscopy indicated that the small nanoparticles of CuO penetrated the cells. Collectively, the results reported herein may reconcile conflicting concepts in the literature concerning the antibacterial mechanism of CuO nanoparticles, as well as highlight the potential for developing sustainable CuO nanoparticles-based devices for inhibiting bacterial infections.

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Anti-Bacterial Agents / pharmacology*
  • Colony Count, Microbial
  • Copper / chemistry
  • Copper / pharmacology*
  • Electron Spin Resonance Spectroscopy
  • Escherichia coli / drug effects
  • Escherichia coli / growth & development
  • Escherichia coli / ultrastructure
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Intracellular Space / drug effects
  • Intracellular Space / metabolism
  • Lipid Peroxidation / drug effects
  • Metal Nanoparticles / chemistry*
  • Mice
  • Microbial Sensitivity Tests
  • Microbial Viability / drug effects
  • Oxidative Stress / drug effects*
  • Particle Size
  • Staphylococcus aureus / drug effects
  • Staphylococcus aureus / growth & development
  • Staphylococcus aureus / ultrastructure
  • Superoxides / metabolism


  • Anti-Bacterial Agents
  • Superoxides
  • Copper
  • Adenosine Triphosphate
  • cupric oxide