The Toxic Effects of Cu and CuO Nanoparticles on Euplotes aediculatus

Abstract

Toxicology tests were carried out by choosing Cu nanoparticles (CuNPs) and CuO nanoparticles (CuONPs) as experimental materials and Euplotes aediculatus as the experimental organism. To investigate the toxicity effect and mechanism of two NPs on E. aediculatus, we determined antioxidant enzyme activity and observed morphologic changes using optical and electron microscopes, combined with the Fourier infrared spectrum technique. The results showed that the 24 h-LC 50 of CuNPs and CuONPs was 0.46 µg/L and 1.24×10 3 µg/L. The movement ability of cells was decreased and surface cilia gradually shed with CuNPs and CuONPs at 24 h-LC 50 . In addition, the cell body swelled and nally ruptured. There were varying extents of damage to the nucleus and mitochondria. With CuNPs, disappearance of nucleoli and condensation of chromatin were observed, while the mitochondria were wrinkled in an irregular shape and cristae were partially fractured. With CuONPs, changes of nucleus were not obvious, and the mitochondria were merely irregular. While neither CuNPs nor CuONPs had major effect on the ultrastructure of the membrane, some functional groups were oxidized with CuNPs, e.g. PO 2 -, C-O-C, δ(COH) of carbohydrates. The 24 h-EC 50 , 48 h-EC 50 and 72 h-EC 50 of CuNPs on E. aediculatus were 2.10×10 -3 µg/L, 7.92×10 -4 µg/L and 2.77×10 -4 µg/L. The EC 50 of CuONPs in same period was 7.20 µg/L, 0.86 µg/L and 0.19 µg/L. The above concentration of CuNPs and CuONPs could increase the activities of SOD, CAT and GPx, which were dose-dependent. The above results indicate that CuNPs and CuONPs inhibited reproduction and caused death. CuNPs were more toxic to E. aediculatus and more destructive to cell structure. Oxidative stress and destruction to cell structures may be toxic mechanisms.The E. aediculatus was more sensitive to CuNPs or CuONPs, and the value of 24 h-LC 50 was much lower than other organisms, so it can be recommended as an indicator for early monitoring in freshwater environment.

Cytotoxicity and Antioxidant Defences in Euplotes aediculatus Exposed to Single and Binary Mixtures of Heavy Metals and Nanoparticles

“…Mortimer et al [38] found ZnO values lower and CuO values higher than our results for the ciliated protozoa T. thermophila at 24 h exposure. According to a study by Zhao et al [44], the LC 50 value of CuO on E. aediculatus was found to be 1.24 mg/L after a 24 h exposure. However, our study showed a higher 24 h LC 50 value of CuO compared to the study by Zhao et al [44].…”

“…According to a study by Zhao et al [44], the LC 50 value of CuO on E. aediculatus was found to be 1.24 mg/L after a 24 h exposure. However, our study showed a higher 24 h LC 50 value of CuO compared to the study by Zhao et al [44]. These different sensitivities may be due to the different origins of the E. aediculatus strains used in the experiments.…”

“…Euplotes aediculatus is a freshwater ciliate belonging to the class Hypotrichea and the family Euplotidae. Although this and other congeneric species have been extensively studied in various biological aspects, including toxicity assessment [40][41][42][43], to the best of our knowledge, only one recent study has attempted to analyse the toxic effects induced by NPs, specifically Cu and CuO, on E. aediculatus [44]. In this regard, our study further extends this analysis by increasing the number of NPs tested (i.e., ZnO, CuO, TiO 2 , and SiO 2 ) and for the first time, assessing their acute and chronic effects in combination with heavy metals (i.e., Cd, Zn, and Cu) on E. aediculatus.…”

Exosome-based drug delivery systems and their therapeutic applications

“…[14][15][16][17][18][19] Although these NPs have been described as potential drug carriers, a major and critical limitation to their application in the biomedical and biotechnological elds is their toxicity prole. [20][21][22][23] Recently, many scientists have shied focus to exosomes as new potential drug carriers and attempted the development of exosome-based DDSs. [24][25][26][27][28][29] Exosomes are a bioproduct that can be obtained from various cell lines such as immune cells, cancer cells, or stem cells as well as from body uids, including blood and cerebrospinal uid.…”

“…14–19 Although these NPs have been described as potential drug carriers, a major and critical limitation to their application in the biomedical and biotechnological fields is their toxicity profile. 20–23…”