Proteomic analysis of the mode of antibacterial action of silver nanoparticles

J Proteome Res. 2006 Apr;5(4):916-24. doi: 10.1021/pr0504079.


Silver nanoparticles (nano-Ag) are potent and broad-spectrum antimicrobial agents. In this study, spherical nano-Ag (average diameter = 9.3 nm) particles were synthesized using a borohydride reduction method and the mode of their antibacterial action against E. coli was investigated by proteomic approaches (2-DE and MS identification), conducted in parallel to analyses involving solutions of Ag(+) ions. The proteomic data revealed that a short exposure of E. coli cells to antibacterial concentrations of nano-Ag resulted in an accumulation of envelope protein precursors, indicative of the dissipation of proton motive force. Consistent with these proteomic findings, nano-Ag were shown to destabilize the outer membrane, collapse the plasma membrane potential and deplete the levels of intracellular ATP. The mode of action of nano-Ag was also found to be similar to that of Ag(+) ions (e.g., Dibrov, P. et al, Antimicrob. Agents Chemother. 2002, 46, 2668-2670); however, the effective concentrations of nano-Ag and Ag(+) ions were at nanomolar and micromolar levels, respectively. Nano-Ag appear to be an efficient physicochemical system conferring antimicrobial silver activities.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / analysis*
  • Anti-Bacterial Agents / pharmacology
  • Bacterial Outer Membrane Proteins / biosynthesis
  • Cell Membrane / physiology*
  • Colony Count, Microbial
  • Dose-Response Relationship, Drug
  • Electrophoresis, Gel, Two-Dimensional
  • Electrophoresis, Polyacrylamide Gel
  • Escherichia coli / drug effects*
  • Escherichia coli / growth & development
  • Fluorescent Antibody Technique, Indirect
  • Immunoblotting
  • Luminescent Measurements
  • Mass Spectrometry
  • Membrane Potentials / drug effects
  • Microscopy, Electron, Transmission
  • Nanostructures
  • Permeability
  • Protein Processing, Post-Translational
  • Proteomics / methods*
  • Protons
  • Silver / chemistry*
  • Silver / pharmacokinetics*
  • Solutions
  • Time Factors


  • Anti-Bacterial Agents
  • Bacterial Outer Membrane Proteins
  • Protons
  • Solutions
  • Silver