The chemical fate of the Cd/Se/Te-based quantum dot 705 in the biological system: toxicity implications.
QD705 is a cadmium/selenium/tellurium (Cd/Se/Te)-based quantum dot with good potential for biomedical applications. Although the biological fate of QD705 is established, its chemical fate in the biological system is still unknown. Since the chemical nature of Cd in QD705 (either stays as bounded Cd or becomes free Cd) is closely related to the toxicity of this nanocrystal, information on its chemical fate is critically needed. In this study we investigated the chemical fate of QD705 in the kidneys of mice. We used the molar ratio of Cd and Te (increased Cd/Te ratio signifies increased Cd release from QD705) and the induction of tissue metallothionein (MT) as markers for elevated free Cd in tissues. Our study indicated that 100% of QD705 (measured as Cd) was still retained in the body 16 weeks after exposure, with significant time redistribution to the kidneys. Furthermore, there were an elevation in both the molar Cd/Te ratio and MT-1 expression in the kidneys, suggesting that free Cd was released from QD705. Thus QD705 is not as stable or biologically inert as many may have once believed. Our study demonstrated that free Cd indeed can be released from QD705 in the kidneys and increases the risk of renal toxicity.
Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Taiwan.
Chia-Hua
CH
Lin
Louis W
LW
Chang
Han
H
Chang
Mo-Hsiung
MH
Yang
Chung-Shi
CS
Yang
Wan-Hau
WH
Lai
Wan-Hsuan
WH
Chang
Pinpin
P
Lin
D000818:Animals; D019187:Cadmium Compounds / Q000493:pharmacokinetics / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D007674:Kidney Diseases / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008422:Materials Testing; D051379:Mice; D008813:Mice, Inbred ICR; D045663:Quantum Dots; D018036:Selenium Compounds / Q000493:pharmacokinetics / Q000633:toxicity*; D013691:Tellurium / Q000493:pharmacokinetics / Q000633:toxicity*
D019187:Cadmium Compounds; D018036:Selenium Compounds; C058667:cadmium selenide; D013691:Tellurium; C028337:cadmium telluride