title: Bioaccumulation and effects of CdTe/CdS quantum dots on Chlamydomonas reinhardtii - nanoparticles or the free ions?
abstract: In order to properly assess the environmental risk of engineered nanoparticles (ENP), it is necessary to determine their fate (including dissolution, aggregation, and bioaccumulation) under representative environmental conditions. CdTe/CdS quantum dots (QD), such as those used in medical imaging, are known to release Cd(2+) due (mainly) to the dissolution of their outer shell. In this study, Chlamydomonas reinhardtii was exposed to either a soluble Cd salt or QD at similar concentrations of total Cd. Free Cd concentrations were measured using the Absence of Gradients and Nernstian Equilibrium Stripping technique. QD dissolution increased with decreasing pH and with increasing QD concentration. When exposed to QD, bioaccumulation was largely accounted for by dissolved Cd. Nonetheless, QD were shown to be taken up by the cells and to provoke unique biological effects. Whole transcriptome screening using RNA-Seq analysis showed that the free Cd and the QD had distinctly different biological effects.
authors.affiliation: Département de Chimie, Université de Montréal, C.P. 6128, succursale Centre-ville, Montréal, Quebec H3C 3J7, Canada. rute.domingos@ist.utl.pt
authors.forename: Rute F
authors.initials: RF
authors.lastname: Domingos
authors.forename: Dana F
authors.initials: DF
authors.lastname: Simon
authors.forename: Charles
authors.initials: C
authors.lastname: Hauser
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Wilkinson
mesh_terms: D002104:Cadmium / Q000378:metabolism* / Q000633:toxicity; D019187:Cadmium Compounds / Q000378:metabolism* / Q000633:toxicity; D016825:Chlamydomonas reinhardtii / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D053758:Nanoparticles; D010316:Particle Size; D045663:Quantum Dots; D012995:Solubility; D013440:Sulfides / Q000378:metabolism* / Q000633:toxicity; D013691:Tellurium / Q000378:metabolism* / Q000633:toxicity
chemical_list: D019187:Cadmium Compounds; D013440:Sulfides; D002104:Cadmium; C034939:cadmium sulfide; D013691:Tellurium; C028337:cadmium telluride