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Interaction of silver nanoparticles of dietary supplements with synthetic stomach fluid
Citation:
Navratilova, J., K. Rogers, K. Bradham, AND J. Harrington. Interaction of silver nanoparticles of dietary supplements with synthetic stomach fluid. QEEN 2, Washington, DC, October 08 - 10, 2018.
Impact/Purpose:
There are a wide range of consumer products that contain colloidal silver (defined as a suspension of particles ranging in size from 1 nm to 1 µm). Many of these products are likely to contain particles in the nanometer size range (1 nm to 100 nm). Given the potential for inhalation exposure of silver nanoparticles from spray disinfectant products, we investigated the gastrointestinal fate of colloidal silver nanoparticles from commercially available consumer products. The products were exposed to synthetic stomach fluid (SSF) to simulate fasting stomach conditions (pH 1.5) as a worst-case scenario for gastrointestinal exposure. The transformation of colloidal silver in these consumer products may have a significant impact on their bioavailability.
Description:
Due to their broad spectrum antimicrobial properties, the use of silver nanoparticles in consumer products, particularly in disinfectant sprays, has increased significantly in recent years. Because of their increasing prevalence, it is important to quantify their potential exposure risk. In this study we investigated the gastrointestinal fate of colloidal silver nanoparticles from commercially available consumer products. The products were exposed to synthetic stomach fluid (SSF) to simulate fasting stomach conditions (pH 1.5) as a worst-case scenario for gastrointestinal exposure. We monitored the aggregation and dissolution of the nanosilver using UV-visible spectroscopy, Dynamic Light Scattering (DLS), Nanoparticle Tracking analysis (NTA), Transmission Electron Microscopy (TEM), and single particle ICP-MS (sp-ICP-MS). Addition of SSF resulted in aggregation, which was observed by NTA, DLS and sp-ICP-MS. Three of the investigated products demonstrated a characteristic plasmon resonance around 400 nm, which dissipated rapidly upon addition of SSF. TEM analysis of the colloidal silver suspensions exhibited an increase in aggregation, as well as the presence of chloride associated with the particle aggregates. Taken together, these results suggest the limited presence of individual silver nanoparticles or free Ag ion in the fasting GI system.