Mechanisms of Silver Nanoparticle Toxicity

• H Autrup

The rapidly growing field of nanotechnology holds great promise for scientific advancement in many sectors such as medicine, consumer
products, energy, and materials. In general terms, nanotechnology covers engineered structures, devices, and systems that have a length scale
between 1 and 100 nanometers. At this size, materials begin to exhibit unique properties that affect physical, chemical, and biological
behavior. However, the same characteristics which make nanomaterials attractive for exploitation in new products have led to concerns that
nanomaterials may pose a risk for humans and the environment. Specific concerns have been raised about the possible toxicity of engineered
nanoparticles (NPs) supported by studies which indicated that NPs are more toxic than larger particles on a mass for mass basis. As a
consequence of their small size, NPs have a very high surface to volume ratio rendering them potentially more reactive than larger particles.
Accordingly, there are strong indications that particle surface area and surface chemistry are responsible for the observed responses in cell
cultures and animals. Silver nanoparticles (Ag NPs) are among the most commonly utilized nanomaterials due to their anti-microbial
properties, high electrical conductivity, and optical properties. Information about the mechanisms involved in the cytotoxicity of Ag NPs is
important in order to evaluate the potential hazards posed by these particles. Several studies have suggested oxidative stress plays a major
role in NP toxicity. But, to what degree and by which mechanism Ag NPs cause oxidative stress in cells is unresolved. The present paper
attempts to critically review the present knowledge about the underlying factors and mechanisms which may influence Ag NP toxicity.

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