Study on the genetic damage caused by cadmium sulfide quantum dots in human lymphocytes

Abstract

Cadmium sulfide quantum dots (CdS QDs) are being developed for sensors, fluorescent probes, and other platforms and are attracting increasing attention. Given the growing demand for QDs, it is clear that there is a need to understand their potential toxicity to organisms. However, little is known regarding the genotoxicity of CdS QDs to humans. Therefore, this study used CdS QDs as the research object, cultured human peripheral blood lymphocytes, and randomly divided them into a control group, CdS I group (CdS QDs), and CdS II group (CdS QDs coated with thioglycolic acid). After cultivation, we measured the olive tail distance, tail length, tail DNA%, lymphocyte micronucleus rate, and aneuploid rate. The comet test results indicated that the indices of the QD group were significantly larger than those of the control group (P < 0.05). The results of the micronucleus and chromosome aberration tests showed that the lymphocyte micronucleus rate and chromosome aneuploid rate in the QD group were significantly increased (P < 0.05) compared with those in the control group. In conclusion, CdS QDs have certain genotoxicity to human peripheral blood lymphocytes, and the DNA damage caused by CdS QDs encapsulated with thioglycolic acid is less severe than that caused by nonencapsulated CdS QDs.

The In Vitro Toxicity Profile of ZnS and CdS Quantum Dots in Polysaccharide Carriers (Starch/Chitosan)

“…In the current study, damage induced by the control composite was at a slightly lower level after short-term exposure. Liu et al [ 34 ] conducted genotoxicity studies of cadmium sulfide quantum dots on human peripheral blood lymphocytes. In the experiment, they used two types of quantum dots: uncoated CdS QDs and CdS QDs surrounded by thioglycolic acid.…”

“…At the same time, based on the second parameter, tail length, they indicated greater toxicity of pure CdS QDs. As a mechanism for this toxicity, they pointed to the ability of QDs to infect cells by endocytosis, and their subsequent effects in cells by generating ROS and oxidative stress, lipid peroxidation, and subsequent DNA damage [ 34 ]. Many studies on metal quantum dots use an additional core coating of ZnS layer to increase photostability and reduce metal efflux from the core, which would reduce the potential toxicity of QDs [ 2 , 6 ].…”

“…Using a micronucleus assay, Grzesiakowska et al [ 33 ] demonstrated the toxic effects of QDsN, observed as a significant increase in the occurrence of micronuclei in cells. Liu et al [ 34 ] conducted a 72 h exposure of human lymphocytes to CdS QDs in a micronucleus assay. The frequency of identified micronuclei was higher for both CdS QD and its thioglycolic acid-coated version.…”

“…As a mechanism of toxicity related to chromosome damage, the authors pointed to the potential ability of quantum dots to inhibit, disrupt, or interrupt cell division. They also showed that surface modification of QDs can effectively retard their harmful effects, but their exact mechanisms of genotoxicity is unknown [ 34 ]. Sharif et al [ 35 ] based on the extremely important biological role of zinc in cells, as a factor affecting cell proliferation, apoptosis, and the development of the immune system, conducted an evaluation of the effects of Zn supplementation or the absence of Zn on human lymphoid cells.…”