Quantum dots have been used in biomedical research for imaging,
diagnostics and sensing purposes. However, concerns over the
cytotoxicity of their heavy metal constituents and conflicting results
from in vitro and small animal toxicity studies have limited their
translation towards clinical applications.
Here, in this paper, a pilot study that rhesus macaques injected with
phospholipid micelleencapsulated CdSe/CdS/ZnS quantum dots do not exhibit
evidence of toxicity. Blood and biochemical markers remained within
normal ranges following treatment, and histology of major organs after
90 days showed no abnormalities. These results showed that acute toxicity of these quantum dots in vivo can be minimal. However, chemical analysis revealed that most of the initial dose of cadmium remained in the liver, spleen and kidneys
after 90 days. This means that the breakdown and clearance of quantum
dots is quite slow, suggesting that longer-term studies will be required
to determine the ultimate fate of these heavy metals and the impact of
their persistence in primates.