In Vivo Toxicity Evaluation of PEGylated CuInS2/ZnS Quantum Dots in BALB/c Mice

Abstract

In recent years, quantum dots (QDs) have emerged as a potential contrast agent for bioimaging due to their bright luminescence and excellent photostability. However, the wide use of QDs <i>in vivo</i> has been limited due to underlying toxicity caused by leakage of heavy metals. Although non-cadmium QDs have been developed to resolve this issue, a comprehensive understanding of the toxicity of these newly developed QDs remains elusive. In this study, we administered PEGylated copper indium sulfide/zinc sulfide (CuInS₂/ZnS), which are typical non-cadmium QDs, and analyzed the long-term effects of these nanoparticles in BALB/c mice. Body weight, hematology, blood biochemistry, organ histology, and biodistribution were examined at different time points. We found no significant difference in body weight after injection of CuInS₂/ZnS QDs. These CuInS₂/ZnS QDs entered and were accumulated in major organs for 90 days post-injection. The majority of biochemical indicators were not significantly different between the QDs-treated group and the control group. In addition, no significant histopathological abnormalities were observed in the treated mice compared with the control mice. CuInS₂/ZnS QDs did not lead to observable toxicity <i>in vivo</i> following either the administration of a high or low dose. Our research not only provides direct evidence of the bio-safety of CuInS₂/ZnS QDs, but also a feasible method for evaluating nanoparticle toxicity.