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Alterations in Physical State of Silver Nanoparticles Exposed to Synthetic Human Stomach Fluid
Citation:
ROGERS, K. R., K. D. BRADHAM, T. M. TOLAYMAT, D. J. THOMAS, T. Hartmann, L. Ma, AND A. WILLIAMS. Alterations in Physical State of Silver Nanoparticles Exposed to Synthetic Human Stomach Fluid. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, Netherlands, 420(March 15, 2012):334-339, (2012).
Impact/Purpose:
The National Exposure Research Laboratory′s (NERL) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA′s mission to protect human health and the environment. HEASD′s research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA′s strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processes that link source emissions, environmental concentrations, human exposures, and target-tissue dose. The impact of these tools is improved regulatory programs and policies for EPA.
Description:
The bioavailability of ingested silver nanoparticles (AgNPs) depends in large part on initial particle size, shape and surface coating, properties which will influence aggregation, solubility and chemical composition during transit of the gastrointestinal tract. Citrate-stabilized AgNPs were exposed to synthetic human stomach fluid (SSF) (pH 1.5) and changes in size, shape, zeta potential, hydrodynamic diameter and chemical composition were determined during a 1 h exposure period using Surface Plasmon Resonance (SPR), High Resolution Transmission ElectronMicroscopy/Energy Dispersive X-ray Spectroscopy (TEM/EDS), Dynamic Light Scattering (DLS) and X-ray Powder Diffraction (XRD) combined with Rietveld analysis. Exposure of AgNPs to SSF produced a rapid decrease in the SPR peak at 414 nm and the appearance of a broad absorbance peak in the near infrared (NIR) spectral region. During exposure to SSF, changes in zeta potential, aggregation and morphology of the particles were also observed as well as production of silver chloride which appeared physically associated with particle aggregates.
URLs/Downloads:
Alterations in Physical State of Silver Nanoparticles Exposed to Synthetic Human Stomach Fluid (PDF, NA pp, 771 KB, about PDF)Science of the Total Environment
