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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

Relationships between SOD activity and accumulated Cu(a) and Ti (b) in D. magna after 48 h exposure to the TiO2 samples prepared with varying RF in the absence and presence of Cu2+. Mean ± standard deviation (n = 3).
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f6: Relationships between SOD activity and accumulated Cu(a) and Ti (b) in D. magna after 48 h exposure to the TiO2 samples prepared with varying RF in the absence and presence of Cu2+. Mean ± standard deviation (n = 3).

Mentions: In the coexistence system, Cu2+ affected the stabilities of TiO2 NS suspensions and their ingestion by organisms. The addition of TiO2 NSs changed Cu2+ uptake and biotoxicity in D. magna. As suggested above, the oxidative stress damage instead of membrane damage is the major toxicity. To further investigate the main mechanisms of oxidative stress toxicity, the relationship between superoxide dismutase (SOD) activity and Cu/Ti accumulation was considered when D. magna was exposed to Cu2+ and different TiO2 samples. According to Fig. 6, a linear relationship between SOD activity and Cu/Ti accumulation in D. magna (P < 0.01, one-way ANOVA) appears. SOD activities decreased with increasing copper accumulation and decreasing Ti accumulation in D. magna. These results are related to the physiological effect of Cu and Ti on organisms.


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)

Relationships between SOD activity and accumulated Cu(a) and Ti (b) in D. magna after 48 h exposure to the TiO2 samples prepared with varying RF in the absence and presence of Cu2+. Mean ± standard deviation (n = 3).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f6: Relationships between SOD activity and accumulated Cu(a) and Ti (b) in D. magna after 48 h exposure to the TiO2 samples prepared with varying RF in the absence and presence of Cu2+. Mean ± standard deviation (n = 3).
Mentions: In the coexistence system, Cu2+ affected the stabilities of TiO2 NS suspensions and their ingestion by organisms. The addition of TiO2 NSs changed Cu2+ uptake and biotoxicity in D. magna. As suggested above, the oxidative stress damage instead of membrane damage is the major toxicity. To further investigate the main mechanisms of oxidative stress toxicity, the relationship between superoxide dismutase (SOD) activity and Cu/Ti accumulation was considered when D. magna was exposed to Cu2+ and different TiO2 samples. According to Fig. 6, a linear relationship between SOD activity and Cu/Ti accumulation in D. magna (P < 0.01, one-way ANOVA) appears. SOD activities decreased with increasing copper accumulation and decreasing Ti accumulation in D. magna. These results are related to the physiological effect of Cu and Ti on organisms.

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