Does particle size and surface functionality affect uptake and depuration of gold nanoparticles by aquatic invertebrates?
Due to the widespread use of engineered nanoparticles (ENPs) in consumer and industrial products it is inevitable that these materials will enter the environment. It is often stated that the uptake of ENPs into organisms in the environment is related to the particle size and surface functionality. To test this assumption, present study investigated the uptake and depuration of gold nanoparticle (Au NPs) coated with either citrate (Au‐citrate NP), mercaptoundecanoic acid (Au‐MUDA NP), amino PEG thiol (Au‐NH2 NP) or PEG (Au‐PEG NP)) by the aquatic invertebrate, Gammarus pulex. The studies were performed using a range of standard ecotoxicity media and natural waters resulting in varying degrees of aggregation of the different NPs. Uptake of gold by G. pulex varied depending on the surface coatings with Au‐MUDA and citrate NPs being taken up to a greater extent than Au‐NH2 and PEG NPs in all test media and natural waters. In all test media evaluated here, higher amounts of amino and PEG coated ENPs were eliminated compared with mercaptoundecanoic acid and citrate coated ENPs. No obvious relationships were seen between the aggregation state of the different study Au NPs in a treatment and uptake, suggesting that the widely accepted assumption that Au NP uptake is related to particle size does not hold for the range of aggregation states studied (67.1 nm – 178.8 nm). Positive correlations between particle number concentration in the media and uptake were observed, indicating that this factor might partly explain the differences in uptake of a particle from different media types. This article is protected by copyright. All rights reserved