The factors that determine the interaction of manufactured nanoparticles (NPs) with biological entities have yet to be fully defined. It will be critical to develop an understanding of these factors to develop materials that do not cause environmental harm and therefore are sustainable.  Surface chemistry in particular may significantly influence NP toxicity by changing NP uptake, interaction with cells and toxicity or by carrying toxic ligands into the organism. In this study, the impacts of differentially functionalized gold and diamond NPs on mortality, reproduction, and body size in the toxicological model species, Daphnia magna, were compared over acute and chronic exposures. Acute assays show that negatively charged gold and diamond NPs are orders of magnitude less toxic than their positively charged counterparts. The results show that certain ligands used in NP functionalization can directly contribute to and increase toxicity of NPs. NPs may also increase the toxicity of ligands by potentially localizing the ligand concentration and exposure. In addition, similarly functionalized diamond and gold NPs differ in their impact on D. magna, which appears to be associated with particle stability. This research indicates NP toxicity is not solely due to surface charge but also may be dependent upon other properties such as ligand density, structure or particle aggregation. These results demonstrate that specific NP properties have great implications for determining NP toxicity and creating sustainable nanotechnologies may involve several aspects of NP design.

Impacts of differeing diamond and gold nanomaterial surface chemistries on toxicity to <i>Daphnia</i> <i>magna</i>: Defining trends in nanomaterial toxicity

248th National Meeting (2014)

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Impacts of differeing diamond and gold nanomaterial surface chemistries on toxicity to Daphnia magna: Defining trends in nanomaterial toxicity