Three-layered silver nanoparticles to trace dissolution and association to a green alga

Nanotoxicology
By: , and 

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Abstract

Core-shell silver nanoparticles (NPs) consisting of an inner Ag core and successive layers of Au and Ag (Ag@Au@Ag) were used to measure the simultaneous association of Ag NPs and ionic Ag by the green alga Chlamydomonas (C.) reinhardtii. Dissolution of the inner Ag core was prevented by a gold (Au) layer, while the outer Ag layer was free to dissolve. In short term experiments, we exposed C. reinhardtii to a range of environmentally realistic Ag concentrations added as AgNO3 or as NPs. Results provide three lines of evidence for the greater cell-association of NPs compared to dissolved Ag over the concentration range tested, assuming that cell-association comprises both uptake and adsorption. First, the cell-association rate constants (kuw) for total Ag (AgNP+D), NPs (AgNP) and AuNP were similar and 2.2-fold higher than the one from AgD exposure, suggesting predominant association of the particles over the dissolved form. Second, model calculations based upon Ag fluxes suggested that only 6-33% of algal burden was from AgD. Thirdly, the significantly lower AgNP/Au ratio measured with the algae after exposure (2.1 ± 0.1) compared to the AgNP/Au ratio of the NPs in the media (2.47 ± 0.05) suggests cell-association of NPs depleted in Ag. Core-shell NPs provide an innovative tool to understand NP behavior and to directly delineate Ag accumulation from ion and NPs in aquatic systems.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Three-layered silver nanoparticles to trace dissolution and association to a green alga
Series title Nanotoxicology
DOI 10.1080/17435390.2019.1640912
Volume 13
Issue 9
Year Published 2019
Language English
Publisher Taylor and Francis
Contributing office(s) WMA - Earth System Processes Division
Description 12 p.
First page 1149
Last page 1160
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