Biodistribution of intact fluorescent CdSe/CdS/ZnS quantum dots coated by mercaptopropionic acid after intravenous injection into mice

Abstract

Semiconductor quantum dots (QD) have been widely used for fluorescent bioimaging. However their biosafety has attracted increasing attention, since the data about their in vivo behavior in biological systems are still limited. In this paper we have investigated the short- and long-term biodistribution of intact fluorescent CdSe/CdS/ZnS QD coated by 3-mercaptopropionic acid in mice. The results showed that intravenously injected QD accumulated mainly in the lungs, liver and spleen and were retained in these tissues for over 22 days. QD caused signs of acute toxicity in mice including death. The investigated QD possibly caused vascular thrombosis. The results of a toxicological assay indicated that some histopathological changes occurred in the lung tissue after the injection of QD. Our study highlights the need for careful evaluation of QD safety before their use in biological applications.