MPA-capped CdTe quantum dots exposure causes neurotoxic effects in nematode Caenorhabditis elegans by affecting the transporters and receptors of glutamate, serotonin and dopamine at the genetic level, or by increasing ROS, or both

Abstract

As quantum dots (QDs) are widely used in biomedical applications, the number of studies focusing on their biological properties is increasing. While several studies have attempted to evaluate the toxicity of QDs towards neural cells, the in vivo toxic effects on the nervous system and the molecular mechanisms are unclear. The aim of the present study was to investigate the neurotoxic effects and the underlying mechanisms of water-soluble cadmium telluride (CdTe) QDs capped with 3-mercaptopropionic acid (MPA) in Caenorhabditis elegans (C. elegans). Our results showed that exposure to MPA-capped CdTe QDs induced behavioral defects, including alterations to body bending, head thrashing, pharyngeal pumping and defecation intervals, as well as impaired learning and memory behavior plasticity, based on chemotaxis or thermotaxis, in a dose-, time- and size-dependent manner. Further investigations suggested that MPA-capped CdTe QDs exposure inhibited the transporters and receptors of glutamate, serotonin and dopamine in C. elegans at the genetic level within 24 h, while opposite results were observed after 72 h. Additionally, excessive reactive oxygen species (ROS) generation was observed in the CdTe QD-treated worms, which confirmed the common nanotoxicity mechanism of oxidative stress damage, and might overcome the increased gene expression of neurotransmitter transporters and receptors in C. elegans induced by long-term QD exposure, resulting in more severe behavioral impairments.

Toxicogenomics of iron oxide nanoparticles in the nematodeC. elegans

“…(Li et al, 2012a, Wu et al, 2015, Scharf et al, 2016 SPION exposure also modulated the expression of clathrin and dynamin, suggesting that SPIONs are taken up via endocytosis, which aligns well with previously reported results. (Tsyusko et al, 2012, Li et al, 2015 SPIONs also exerted significant effects on the expression of genes involved in the structure and integrity of the intestinal barrier (act-5, eps-8 and elt-2).…”

DNA damage in BV‐2 cells: An important supplement to the neurotoxicity of CdTe quantum dots

“…In our opinion, the concentrations of Cd may be a better index for determining the toxicity of QDs than the molar concentration of the QD particles. The differences among the molar concentrations of the three QDs were large, but according to our former study, there was a narrow difference in cytotoxicity between the 2.2 and 3.5 nm QDs (Wu et al, ; Wu, He, Zhan, Ang, et al, ; Wu, et al, ). Therefore, we recommend the use of Cd concentrations as an indicator among laboratories worldwide.…”

Perovskite Quantum Dots and Their Application in Light‐Emitting Diodes

“…Perovskite QD (PQD)‐based QLEDs recently drew significant attention given their extra‐narrow emission wavelength, which measures lower than 20 nm. QDs can be mainly separated into three types, namely, Cd‐based QDs (CdSe, CdTe, and PbS), Cd‐free QDs (InP, CuInS 2 ), and PQDs (methylammonium (MA)PbBr 3 , CsPbBr 3 ). PQDs feature the typical chemical composition of ABX 3 , where A represents cesium (Cs), MA, or formamidinium (FA); B represents a metal cation (Pb, Sn); and X is a halide anion (Cl, Br, and I)).…”