Transfer of Quantum Dots from Pregnant Mice to Pups Across the Placental Barrier

Fluorescent quantum dots (QDs) have great potential for in vivo biomedical imaging and diagnostic applications. However, these nanoparticles are composed of heavy metals and are very small in diameter, and their possible toxicity must therefore be considered. As yet, no studies have reported the transfer of QDs between mother and fetus. The transfer of CdTe/CdS QDs of different sizes and dosages, and with different outer capping materials, from pregnant mice to fetuses is investigated. It is shown that QDs may be transferred from female mice to their fetuses across the placental barrier. Smaller QDs are more easily transferred than larger QDs and the number of QDs transferred increases with increasing dosage. Capping with an inorganic silica shell or organic polyethylene glycol reduces QD transfer but does not eliminate it. These results suggest that the clinical utility of QDs could be limited in pregnant women. The effects of injecting Cd‐containing quantum dots (QDs) into pregnant mice are investigated. It is found that the QDs may penetrate the placental barrier, depending on QD size, dosage, and capping material. The risk is greater with QDs containing higher levels of Cd and for smaller QDs, since more Cd is transferred to the fetuses. Although coating QDs with PEG or SiO2 reduces the QD and Cd2+ ion transfer, some Cd is still detected in pups of injected mothers.