Silver nanoparticles (AgNPs) have antimicrobial properties and, therefore, they are largely used in pharmaceutical or food industries. Human exposure to AgNPS, however, might be harmful.

Frank Kjeldsen, University of Southern Denmark, Odense M, Denmark, and co-workers investigated the biochemical events occurring in colon cells following AgNPs exposure. The analysis revealed that AgNPs trigger a cellular stress whose magnitude depends on the particles’ size.
20 nm nanoparticles enter the cells and directly affect their metabolism by inducing reactive oxygen species, DNA damage, post-translational modifications (such as protein SUMOylation and ubiquitination), and apoptosis (a programmed cell death). By contrast, 100 nm nanoparticles mostly remain outside the cells and thus induce indirect effects by activating protein kinases such as MAPK and PAK, and protein phosphates.

AgNPs, thus, deeply affect the biochemistry of colon cells. This aspect should be taken into account for designing newer and safer AgNPs.

• Insights into the Cellular Response Triggered by Silver Nanoparticles Using Quantitative Proteomics,
  Thiago Verano-Braga, Rona Miethling-Graff, Katarzyna Wojdyla, Adelina Rogowska-Wrzesinska, Jonathan R. Brewer, Helmut Erdmann, Frank Kjeldsen,
  ACS Nano 2014, 8, 2161–2175.
  DOI: 10.1021/nn4050744