AVS 64th International Symposium & Exhibition
    Biomaterial Interfaces Division Wednesday Sessions
       Session BI+AS-WeA

Paper BI+AS-WeA4
Linking Nanosilver (AgNP) Toxicity to the Physicochemical Properties of the Particles which can Change as a Function of Experimental and Biological Conditions

Wednesday, November 1, 2017, 3:20 pm, Room 12

Session: In Honor of Dave Castner's 65th Birthday: Multitechnique Bio-Surface Characterization II
Presenter: Donald Baer, Pacific Northwest National Laboratory
Authors: D.R. Baer, Pacific Northwest National Laboratory
J.M. Brown, University of Colorado at Denver
A. Porter, Imperial College London, UK
B.D. Thrall, Pacific Northwest National Laboratory
T.D. Tetley, Imperial College London, UK
L.S. Van Winkle, University of California at Davis
T. Xia, University of California at Los Angeles
Correspondent: Click to Email
Although colloidal Ag is generally considered safe for humans, use of nanosilver in consumer products has dramatically increased both the amount of Ag exposure and possible exposure pathways. To fill knowledge gaps for nano-Ag safety assessment, the National Institute of Environmental Health Sciences supported a consortium of investigators to examine how physical and chemical characteristics of AgNPs can lead to adverse health outcomes. Here we report a consortium perspective linking physicochemical properties of the particles to Ag biodistribution and toxicity. It is necessary to recognize the dynamic nature of AgNPs. They can change in response to handling and variations in their environment and such changes can influence Ag biodistribution and biological responses. Consortium studies identified the critical relationships among AgNP properties, environmental effects, and the biodistribution and fate of Ag associated with the particles. Three critical regions of interactions were identified: i) effect of exposure medium and biological environment on particle properties and transformations; ii) processes occurring at the cellular surface impacting particle attachment, uptake, accumulation and clearance; and iii) particle fate and transformations within a cell. The nature of AgNPs during biological exposure is influenced by the initial characteristics of the particles including size, structure and the presence of designed or inadvertent coatings. These initial properties are usually altered by exposure to artificial or natural media. These physicochemical properties are often time dependent and such changes, including often ignored effects due to handling or storage, can influence biological outcomes. Ag can be transported into cells as both ions and particles. While ions are known to impact cytotoxicity, AgNPs within cells often have greater toxicity. Intercellular processes are similar to those in extracellular media except that the Ag is located within specific microenvironments within a cell. It appears that intracellular dissolution of Ag is a major cause of toxicity.