title: Adsorption, uptake and distribution of gold nanoparticles in Daphnia magna following long term exposure.
abstract: Gold nanoparticles (nAu) have recently been studied and developed within the biological and photothermal therapeutic contexts. The major clinical interest is within the application of novel drug delivery systems. Environmental exposure to nanoparticles can occur in different stages of the lifecycle of the product; from their synthesis, applications, product weathering and their disposal. Freshwater Daphnids, specifically Daphnia magna, have been used since the 1960s as a standard species in acute and chronic aquatic toxicity testing. Visualization of the interactions and uptake of nAu by D. magna was related to reproduction and molting patterns. Exposure to nAu was done using a chronic reproduction test performed for 14 days at six concentrations (0.5mg/L, 2mg/L, 5mg/L, 10mg/L, 15mg/L and 20mg/L). Microscopy was used to determine whether there was any uptake or interaction of nAu with daphnia. However the concentration of nAu in the media and the charge of particles played a role in the uptake and surface adsorption. As exposure concentrations of nAu increased it appeared that the nAu aggregated onto the surface and in the gut of the organisms in higher concentrations. There was no evidence of nAu internalization into the body cavity of the daphnia. Aquatic exposure to nAu resulted in increased adhesion of the particles to the carapace of daphnia, ingestion and uptake into the gut of daphnia and had no significant effect on reproduction and molting patterns.
authors.affiliation: Unit for Environmental Sciences and Management, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa. Electronic address: tlbothanano@gmail.com.
authors.forename: Tarryn Lee
authors.initials: TL
authors.lastname: Botha
authors.affiliation: Toxicology Department, NIOH Hospital Street, Johannesburg, South Africa.
authors.forename: Kailen
authors.initials: K
authors.lastname: Boodhia
authors.affiliation: Unit for Environmental Sciences and Management, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa.
authors.forename: Victor
authors.initials: V
authors.lastname: Wepener
mesh_terms: D000327:Adsorption; D000818:Animals; D003621:Daphnia / Q000187:drug effects / Q000502:physiology*; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000032:analysis* / Q000633:toxicity; D008853:Microscopy; D012098:Reproduction / Q000187:drug effects; D014018:Tissue Distribution; D036401:Toxicity Tests, Chronic; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics* / Q000633:toxicity
chemical_list: D014874:Water Pollutants, Chemical; D006046:Gold
keywords: Adhesion; Body burden; CytoViva; Molts