AGNPS, SILVER NANOPARTICLES AND HEALTH CONCERNS: A REVIEW ON IN VITRO AND IN VIVO TOXICITY

Silver (Ag) nanoparticles (AgNPs) are among the most commercially utilized nanoparticles worldwide. Nanosilver particles are generally smaller than 100 nm and contain 20-15,000 silver atoms. At the nanoscale, silver exhibits remarkable physical, chemical and biological properties, thus they are highly interesting for the creation of novel and advanced functional materials. Due to its strong antibacterial activity, nanosilver coating is used on various manufactured textiles as well as cardiovascular implants, and central venous or neurosurgical catheters. Furthermore, nanosilver is a component of burn treatment wound dressings, cosmetics and contraceptive devices. It has been marketed as a water disinfectant, room spray and used in the food industry. Despite its widespread use, very little data exist in terms of possible adverse effects on human health including their short- and long-term toxicities. Inflammatory, oxidative, genotoxic, and cytotoxic consequences have been associated with silver particulate exposure, and are inherently linked as shown in in vitro studies. In in vivo models, it has been consistently demonstrated that the primary site of silver particulate accumulation is the liver; therefore, a number of in vitro investigations have focused on this target organ. However, in general, in vivo and in vitro toxicity information that would allow correlations between findings are still lacking. Sufficient information in the existing literature is available on tissue absorption, distribution, metabolism, and excretion of AgNPs following exposure which could be useful in directing appropriate in vitro experimentation by revealing other potential target sites of toxicity. The present review focuses on the importance for human health of in vitro and in vivo toxicity studies related to the use of AgNPs in mammalian animal models. Studies of AgNP toxicity in a nonmammalian animal model, Zebrafish (Danio rerio), which shares close homology with the human genome, are also reported. More comprehensive studies are required to fully understand the toxicities associated with silver nanoparticle exposure in order to assure their safe use in medical and industrial applications.