Limits...
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

SOD enzyme(a) and Na+/K+-ATPase (b) activities in D. magna after 48 h exposure to the prepared NP10, NS61, NS71, NS74 and NS78 samples in the absence and presence of Cu2+. Mean ± standard deviation (n = 3), (P < 0.05, one-way ANOVA).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4525146&req=5

f5: SOD enzyme(a) and Na+/K+-ATPase (b) activities in D. magna after 48 h exposure to the prepared NP10, NS61, NS71, NS74 and NS78 samples in the absence and presence of Cu2+. Mean ± standard deviation (n = 3), (P < 0.05, one-way ANOVA).

Mentions: The SOD enzyme activities in D. magna were investigated because they are antioxidant biomarkers for oxidative stress. As shown in Fig. 5a, when D. magna was exposed only to different nano-sized TiO2, the SOD enzyme activity decreased from 55.5% to 86.6% compared with the control experiment. SOD enzyme activities increased with increasing percentage of {001} facet of TiO2 NSs, although the NS78 sample had the largest Ti accumulation. When D. magna was exposed to different TiO2 and Cu2+, SOD activity decreased by 31.0% to 64.7% compared with the control experiment (only Cu2+). The decrease in SOD activities indicated that both TiO2 and Cu2+ induced a certain degree of oxidative stress and SOD enzyme inactivation30. The nanotoxicity theories were generated by the reactive oxygen species (ROS) and oxidative stress effects31. Nanoparticle stress resulting in ROS generation has already been reported by the Dalai groupand could be related to TiO2 NP cytotoxicity potential32. When D. magna was exposed to two foreign materials, SOD activities in the organisms were further deactivated. In addition, SOD activities in the exposed group were evidently lower than Cu2+ only, implying that Cu and nano-sized TiO2 together are more dangerous than Cu alone in aquatic environments.


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)

SOD enzyme(a) and Na+/K+-ATPase (b) activities in D. magna after 48 h exposure to the prepared NP10, NS61, NS71, NS74 and NS78 samples in the absence and presence of Cu2+. Mean ± standard deviation (n = 3), (P < 0.05, one-way ANOVA).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: SOD enzyme(a) and Na+/K+-ATPase (b) activities in D. magna after 48 h exposure to the prepared NP10, NS61, NS71, NS74 and NS78 samples in the absence and presence of Cu2+. Mean ± standard deviation (n = 3), (P < 0.05, one-way ANOVA).
Mentions: The SOD enzyme activities in D. magna were investigated because they are antioxidant biomarkers for oxidative stress. As shown in Fig. 5a, when D. magna was exposed only to different nano-sized TiO2, the SOD enzyme activity decreased from 55.5% to 86.6% compared with the control experiment. SOD enzyme activities increased with increasing percentage of {001} facet of TiO2 NSs, although the NS78 sample had the largest Ti accumulation. When D. magna was exposed to different TiO2 and Cu2+, SOD activity decreased by 31.0% to 64.7% compared with the control experiment (only Cu2+). The decrease in SOD activities indicated that both TiO2 and Cu2+ induced a certain degree of oxidative stress and SOD enzyme inactivation30. The nanotoxicity theories were generated by the reactive oxygen species (ROS) and oxidative stress effects31. Nanoparticle stress resulting in ROS generation has already been reported by the Dalai groupand could be related to TiO2 NP cytotoxicity potential32. When D. magna was exposed to two foreign materials, SOD activities in the organisms were further deactivated. In addition, SOD activities in the exposed group were evidently lower than Cu2+ only, implying that Cu and nano-sized TiO2 together are more dangerous than Cu alone in aquatic environments.

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