Safety evaluation of hair-dryers marketed as emitting nano silver particles

Nanoparticle infused personal care products are becoming more common as consumer products. One example is a hair-dryer marketed as emitting silver nanoparticles (Ag NPs). The purpose of the silver nanoparticles (Ag NPs) is to give hair a sleek, shiny look while also promoting antimicrobial effects. This study investigates release of Ag NPs from hair-dryers and the effects associated with Ag NPs to the human epidural flora. To give an estimation of consumer exposure to Ag NPs with these products, three brands of hair-dryers were selected and particle samples emitted from the hair-dryers were collected based on size fractionation. Collected particles underwent elemental analysis. Silver was not detected in any of the samples. The Kirby-Bauer assay was used to detect a toxicity dose response relationship over a range of silver nanoparticles and silver nitrate (AgNO3) concentrations using five model bacteria species. This portion of the work represented the microbial response to Ag NPs and acted as a proxy for epidural microbial exposure to Ag NPs emitted from a hair-dryer. Findings from this study such as the recorded release of nanoparticles from the hair-dryers and the potential microbial toxicity effects caused from nanoparticle exposure will help consumers make more informed decisions regarding nanoparticle infused products.