The effects of sub-lethal concentrations of silver nanoparticles on inflammatory and stress genes in human macrophages using cDNA microarray analysis

Because of the limited information on size-dependent particle-mediated effects, the present study was conducted to determine if the changes in induced protein expression between 5 nm silver nanoparticles and 100 nm particles after exposure to sub-lethal concentrations. A total of 28,000 cDNA profiles were screened using 5 nm silver nanoparticles and 100 nm silver nanoparticles in a macrophage cell line. Based on results obtained from cDNA microarray we also assessed protein levels of hemeoxygenase-1 (HO-1), heat shock protein-70 (HSP-70) and interleukin-8 (IL-8), which were shown to significantly increase. Together with results obtained using N-acetylcystein (NAC), we were able to clearly show that low level and early stage exposure to 5 nm silver nanoparticles, but not 100 nm, induces expression of IL-8 as well as stress genes against reactive oxygen species (ROS). Therefore, we provide important data to understand and identify the early effects of silver nanoparticles on the immune system. (C) 2012 Elsevier Ltd. All rights reserved.