Abstract
Silver nanoparticles (AgNPs) induce the production of reactive oxygen species (ROS) and apoptosis. These effects are enhanced by smaller particles. Using live-cell imaging, we show that AgNPs induced ROS production rapidly in a size-dependent manner after exposure of cells to 70-nm and 1-nm AgNPs (AgNPs-70, AgNPs-1), but not AgNO(3). Exposure of cells to 5 μg/mL each of AgNPs-70, AgNPs-1 or AgNO(3) for 1 h decreased the cell viability by approximately 40%, 100% and 20%, respectively. ROS were rapidly induced after 5 and 60 min by AgNPs-1 and AgNPs-70, respectively, whereas AgNO(3) had no detectable effect. ROS production detected using the reporter dichlorodihydrofluorescein was observed in whole cells and mitochondria 5 and 60 min after exposure to AgNPs-1. The present study is the first, to our knowledge, to report the temporal expression and intracellular localisation of ROS induced by AgNPs.