Abstract
Quantum dots (QDs) has been wildly used for biomedical applications and show exceptional competence to be the same as the organic dyes due to their superior optical properties and conjugation diversity. However, as being applied into living animals, the concern of the notoriously unusual and cadmium-containing nanostructures made QDs to be the two sides of the same coin and elicit many paradoxical viewpoints. For the safety considerations in vivo, analytical methods were developed for the direct investigation of the QD biodistribution that became a flourishing issue to be invested urgently. Based on the reports regarding the biodistribution data of QDs, in general, the total concentrations of QDs in blood and homogenized organs or tissues were used. Neither the detailed QD distribution among the compartments of blood stream, extracellular space, and that be fixed by cells nor the integrity following the cadmium release was performed because it was still lack of the suitable analytical strategies to deeply explore the QD extravasation and the behavior of cadmium release in living animals. To overcome the abovementioned limitations, the PTFE tubing-based sample pretreatment schemes were hyphenated to push-pull perfusion sampling and ICP-MS for not only the analysis of QDs in liver extracellular space but also the QD integrity based on its cadmium release behavior. According to the results acquired, the functional groups on QD surface had an obvious influence on their blood pharmacokinetics, extracellular profiles, and liver accumulation. Besides, within the 5-h monitoring, it was indicated that pegylated QDs can still sustain its integrity with the negligible release of the constituent elements. Based on the superiority and uniqueness of our developed methods, it is expected that a strong network of nano-related analytical chemist, pharmacologist and toxicologist can be established for the purpose of exploring and mapping the secret of QDs in vivo.