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Effects of the interaction between TiO2 with different percentages of exposed {001} facets and Cu(2+) on biotoxicity in Daphnia magna.

Liu L, Fan W, Lu H, Xiao W - Sci Rep (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Science and Engineering, School of Chemistry and Environment, Beihang University, Beijing 100191, Beijing, P. R.China.

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.

No MeSH data available.


Related in: MedlinePlus

(a) Accumulated copper after 48 h exposure to 50 μg/L Cu2+ with or without 1 mg/L of the prepared NP10, NS61, NS71, NS74 and NS78 samples (P < 0.05, one-way ANOVA). (b) Relationship of copper accumulation in D. magna and Cu2+ concentration in the supernate when Cu2+ and TiO2 coexisted and reached a steady state in water. Mean ± standard deviation (n = 3).
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f4: (a) Accumulated copper after 48 h exposure to 50 μg/L Cu2+ with or without 1 mg/L of the prepared NP10, NS61, NS71, NS74 and NS78 samples (P < 0.05, one-way ANOVA). (b) Relationship of copper accumulation in D. magna and Cu2+ concentration in the supernate when Cu2+ and TiO2 coexisted and reached a steady state in water. Mean ± standard deviation (n = 3).

Mentions: Cu accumulation in D. magna at different exposure conditions was investigated in this study, as shown in Fig. 4a. Compared with the control experimental run (treated only with Cu2+), the existence of TiO2 also influenced the bioaccumulation of Cu2+ in D. magna. When D. magna was exposed to water with a mixture of Cu2+ and NP10, Cu2+ accumulation was enhanced by 9.8%. However, Cu2+ accumulation in D. magna was reduced by 43% to 53% when Cu2+ coexisted with TiO2 NSs. Generally, the forms of Cu2+ ingested by D. magna were free Cu2+ and adsorbed Cu2+ on TiO2. When copper coexisted with TiO2, TiO2 could adsorb Cu2+. Thus its free ion concentration decreased in the ambient environment, which diminished a portion of Cu2+ internalization and bioavailability. In contrast, Cu2+ accumulation was enhanced when D. magna swallowed Cu2+-adsorbed TiO2. The factor that dominates in Cu accumulation depends on the unique physicochemical characteristics of TiO2 and exposure condition.


Effects of the interaction between TiO2 with different percentages of exposed {001} facets and Cu(2+) on biotoxicity in Daphnia magna.

Liu L, Fan W, Lu H, Xiao W - Sci Rep (2015)

(a) Accumulated copper after 48 h exposure to 50 μg/L Cu2+ with or without 1 mg/L of the prepared NP10, NS61, NS71, NS74 and NS78 samples (P < 0.05, one-way ANOVA). (b) Relationship of copper accumulation in D. magna and Cu2+ concentration in the supernate when Cu2+ and TiO2 coexisted and reached a steady state in water. Mean ± standard deviation (n = 3).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525146&req=5

f4: (a) Accumulated copper after 48 h exposure to 50 μg/L Cu2+ with or without 1 mg/L of the prepared NP10, NS61, NS71, NS74 and NS78 samples (P < 0.05, one-way ANOVA). (b) Relationship of copper accumulation in D. magna and Cu2+ concentration in the supernate when Cu2+ and TiO2 coexisted and reached a steady state in water. Mean ± standard deviation (n = 3).
Mentions: Cu accumulation in D. magna at different exposure conditions was investigated in this study, as shown in Fig. 4a. Compared with the control experimental run (treated only with Cu2+), the existence of TiO2 also influenced the bioaccumulation of Cu2+ in D. magna. When D. magna was exposed to water with a mixture of Cu2+ and NP10, Cu2+ accumulation was enhanced by 9.8%. However, Cu2+ accumulation in D. magna was reduced by 43% to 53% when Cu2+ coexisted with TiO2 NSs. Generally, the forms of Cu2+ ingested by D. magna were free Cu2+ and adsorbed Cu2+ on TiO2. When copper coexisted with TiO2, TiO2 could adsorb Cu2+. Thus its free ion concentration decreased in the ambient environment, which diminished a portion of Cu2+ internalization and bioavailability. In contrast, Cu2+ accumulation was enhanced when D. magna swallowed Cu2+-adsorbed TiO2. The factor that dominates in Cu accumulation depends on the unique physicochemical characteristics of TiO2 and exposure condition.

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Science and Engineering, School of Chemistry and Environment, Beihang University, Beijing 100191, Beijing, P. R.China.

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.

No MeSH data available.


Related in: MedlinePlus