title: Effects of the interaction between TiO2 with different percentages of exposed {001} facets and Cu(2+) on biotoxicity in Daphnia magna.
abstract: Anatase TiO2 nanosheets (NSs) with exposed {001} facets have been widely used because of their high activity and particular surface atomic configuration. However, investigations on their biotoxicity are rare. In this study, bioaccumulation of five different TiO2 (with 10%, 61%, 71%, 74% and 78% exposed {001} facets), as well as copper and enzyme activities in Daphnia magna, are systematically investigated and rationalized. The results indicated that the addition of Cu(2+) enhanced agglomeration-sedimentation of TiO2, resulting in the reduction of TiO2 bioaccumulation by 10% to 26%. TiO2 nanoparticles (NPs) increased copper bioaccumulation by 9.8%, whereas the other four TiO2 nanosheets (NSs) decreased it by 43% to 53%, which depended on TiO2 variant adsorption and free Cu(2+) concentrations in the supernatant. The levels of superoxide dismutase (SOD) enzyme and Na(+)/K(+)-ATPase activities suggested that oxidative stress, instead of membrane damage, was the main toxicity in D. magna. Meanwhile, the SOD enzyme activities increased with decreasing Cu accumulation and increasing Ti accumulation because of the different functions of Cu and Ti in organisms. This research highlighted the important role of the percentage of exposed {001} facets in nanostructured TiO2 on bioaccumulation and biotoxicity of TiO2 and Cu(2+) in Daphnia magna.
authors.affiliation: Department of Environmental Science and Engineering, School of Chemistry and Environment, Beihang University, Beijing 100191, Beijing, P. R.China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Environmental Science and Engineering, School of Chemistry and Environment, Beihang University, Beijing 100191, Beijing, P. R.China.
authors.forename: Wenhong
authors.initials: W
authors.lastname: Fan
authors.affiliation: Department of Environmental Science and Engineering, School of Chemistry and Environment, Beihang University, Beijing 100191, Beijing, P. R.China.
authors.forename: Huiting
authors.initials: H
authors.lastname: Lu
authors.affiliation: Department of Environmental Engineering, School of Resource &Environmental Sciences, Wuhan University, Wuhan 430072, Hubei, P. R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
mesh_terms: D000818:Animals; D003300:Copper / Q000737:chemistry*; D003621:Daphnia / Q000187:drug effects* / Q000378:metabolism; D007477:Ions / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity; D023421:Models, Animal; D049329:Nanostructures / Q000737:chemistry* / Q000633:toxicity / Q000648:ultrastructure; D018384:Oxidative Stress / Q000187:drug effects; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D014025:Titanium / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000633:toxicity
chemical_list: D007477:Ions; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D003300:Copper; D014025:Titanium; D013482:Superoxide Dismutase; D000254:Sodium-Potassium-Exchanging ATPase