Synthesis and antibacterial activity of silver nanoparticles against gram-positive and gram-negative bacteria

Nanomedicine. 2012 Jan;8(1):37-45. doi: 10.1016/j.nano.2011.05.007. Epub 2011 Jun 2.


Synthesis of nanosized particles with antibacterial properties is of great interest in the development of new pharmaceutical products. Silver nanoparticles (Ag NPs) are known to have inhibitory and bactericidal effects. In this article we present the synthesis of Ag NPs prepared by chemical reduction from aqueous solutions of silver nitrate, containing a mixture of hydrazine hydrate and sodium citrate as reductants and sodium dodecyl sulfate as a stabilizer. The results of the characterization of the Ag NPs show agglomerates of grains with a narrow size distribution (from 40 to 60 nm), whereas the radii of the individual particles are between 10 and 20 nm. Finally, the antibacterial activity was measured by the Kirby-Bauer method. The results showed reasonable bactericidal activity against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The standard dilution micromethod, determining the minimum inhibitory concentration leading to inhibition of bacterial growth, is still under way. Preliminary results have been obtained.

From the clinical editor: In this paper the synthesis of Ag NPs via chemical reduction from aqueous solutions is discussed. Reasonable bactericidal activity against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus was demonstrated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / chemistry*
  • Anti-Bacterial Agents / pharmacology*
  • Citrates / chemistry
  • Disk Diffusion Antimicrobial Tests
  • Escherichia coli / drug effects
  • Gram-Negative Bacteria / drug effects*
  • Gram-Positive Bacteria / drug effects*
  • Humans
  • Hydrazines / chemistry
  • Metal Nanoparticles / chemistry*
  • Pseudomonas aeruginosa / drug effects
  • Silver / chemistry*
  • Silver / pharmacology*
  • Sodium Citrate
  • Sodium Dodecyl Sulfate / chemistry
  • Spectrophotometry, Ultraviolet
  • Staphylococcus aureus / drug effects
  • Surface Plasmon Resonance


  • Anti-Bacterial Agents
  • Citrates
  • Hydrazines
  • Sodium Citrate
  • hydrazine
  • Sodium Dodecyl Sulfate
  • Silver