Detection of Bacterial Contamination in Nanoparticle Formulations by Agar Plate Test

Methods Mol Biol. 2018;1682:19-22. doi: 10.1007/978-1-4939-7352-1_2.


Bacterial contamination can confound the results of in vitro and in vivo preclinical tests. This protocol describes a procedure for detection of microbial contamination in nanotechnology-based formulations. Nanoparticle samples and controls are spread on the surface of agar and growth of bacterial colonies is monitored after 72 h of incubation. The intended purpose of this assay is to avoid introduction of microbial contamination into in vitro cell cultures and in vivo animal studies utilizing the test nanomaterial. This assay is not intended to certify the material as sterile.

Keywords: Bacteria; Contamination; Mold; Nanoparticles; Yeast.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Agar / chemistry
  • Animals
  • Bacteria / growth & development*
  • Bacteria / isolation & purification
  • Colony Count, Microbial / methods*
  • Equipment Contamination
  • Humans
  • Nanoparticles / microbiology*


  • Agar