Bioaccumulation of CdTe quantum dots in a freshwater alga Ochromonas danica: a kinetics study.
The bioaccumulation kinetics of thioglycolic acid stabilized CdTe quantum dots (TGA-CdTe-QDs) in a freshwater alga Ochromonas danica was comprehensively investigated. Their photoluminescence (PL) was determined by flow cytometry. Its cellular intensity increased hyperbolically with exposure time suggesting real internalization of TGA-CdTe-QDs. This hypothesis was evidenced by the nanoparticle uptake experiment with heat-killed or cold-treated cells and by their localization in the vacuoles. TGA-CdTe-QD accumulation could further be well simulated by a biokinetic model used previously for conventional pollutants. Moreover, macropinocytosis was the main route for their internalization. As limited by their diffusion from the bulk medium to the cell surface, TGA-CdTe-QD uptake rate increased proportionally with their ambient concentration. Quick elimination in the PL of cellular TGA-CdTe-QDs was also observed. Such diminishment resulted mainly from their surface modification by vacuolar biomolecules, considering that these nanoparticles remained mostly undissolved and their expulsion out of the cells was slow. Despite the significant uptake of TGA-CdTe-QDs, they had no direct acute effects on O. danica. Overall, the above research shed new light on nanoparticle bioaccumulation study and would further improve our understanding about their environmental behavior, effects and fate.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University , Nanjing, Jiangsu Province, 210046, China.
Ying
Y
Wang
Ai-Jun
AJ
Miao
Jun
J
Luo
Zhong-Bo
ZB
Wei
Jun-Jie
JJ
Zhu
Liu-Yan
LY
Yang
D019187:Cadmium Compounds / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D005618:Fresh Water; D007700:Kinetics; D008163:Luminescent Measurements; D008954:Models, Biological; D044663:Ochromonas / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D045663:Quantum Dots / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D013691:Tellurium / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D013864:Thioglycolates / Q000737:chemistry
D019187:Cadmium Compounds; D013864:Thioglycolates; C017487:2-mercaptoacetate; D013691:Tellurium; C028337:cadmium telluride