| AVS 61st International Symposium & Exhibition | |
| Biomaterial Interfaces | Monday Sessions |
| Session BI+AS+NS-MoA |
| Session: | Bio/Nano Interfaces |
| Presenter: | Donald Baer, Pacific Northwest National Laboratory |
| Authors: | P. Munusamy, Pacific Northwest National Laboratory J.N. Smith, Pacific Northwest National Laboratory C. Liu, Pacific Northwest National Laboratory C.-M. Wang, Pacific Northwest National Laboratory S. Chen, Imperial College London, UK M.H. Engelhard, Pacific Northwest National Laboratory A.E. Porter, Imperial College London, UK M.P. Ryan, Imperial College London, UK D.R. Baer, Pacific Northwest National Laboratory |
| Correspondent: | Click to Email |
The wide-spread use of silver nanoparticles in consumer products raises questions of environmental impact and toxicity. Because both silver particles, and silver ions formed by particle dissolution, may impact biological systems, it is important to understand the characteristics of silver nanoparticles as they are made and their stability and dissolution in the medium relevant to environmental and toxicological studies. Silver nanoparticles produced by different synthesis routes can have significantly varying physical and chemical characteristics. In this talk we will summarize the characterization and dissolution stability of three types of silver nanoparticles (20 nm particles synthesized with and without gold core (~7 nm) and 110 nm particles with gold core) in cell culture media with serum proteins: FBS10%/RPMI, the culture media used at Pacific Northwest National Laboratory for in-vitro toxicity studies. These nanoparticles were synthesized and prepared for biological study in aqueous solution. They were examined in situ using dynamic light scattering, zeta potential measurements and optical adsorption and ex situ with x-ray photoelectron spectroscopy and transmission electron microscopy. For the dissolution studies, concentrations of particles examined were varied from 1 µg/ml to 50 µg/ml, consistent with the range of concentrations typically used during in-vitro studies. Silver particles with gold cores had smaller crystallite size and higher apparent solubility than three different batches of pure ~ 20 nm silver particles. A simple dissolution model was found to describe the time variation of particle size and amount of dissolved silver for particle loadings above 9 µg/ml. The effective solubility product obtained from fitting the data was higher for the 20 nm particles with the gold core in comparison to the pure silver or 110 nm particles. The dissolution of silver nanoparticles was also found to be enhanced by presence of serum proteins contained in fetal bovine serum (FBS). In addition, the protocol of dispersion in cell culture medium was found to influence particle agglomeration and the rate of dissolution. In these measurements focusing on a 24 hour time point, we found that the structure of the silver nanoparticles can have a significant impact on the concentration of dissolved silver in media and thus the dosimetry to which cells would be exposed during in vitro studies.
This work has been supported by the NIEHS under Center grant U19 ES019544. Portions of this work were performed using EMSL, a national scientific user facility sponsored by the US Department of Energy, Biological and Environmental Research and located at PNNL.