Real-Time Imaging of Endocytosis and Intracellular Trafficking of Semiconducting Polymer Dots.

Semiconducting polymer dots (Pdots) have shown great promise in biomedical applications, including biosensing, drug delivery, and live imaging of cells and biomolecules. Insight into the mechanism and regulation of cellular uptake and intracellular metabolism of Pdots is important for the development of superior Pdots-based theranostic nanoconjugates. Herein, we performed real-time imaging of endocytosis and intracellular trafficking of a type of fluorescent Pdots that showed excellent biocompatibility in various types of cells. The endocytic routes and kinetics of Pdots were differently regulated in distinct cell types. Following endocytosis, Pdots were transported in vesicles along microtubule and destined for lysosomes. Furthermore, our results revealed exosome-mediated extracellular release of Pdots and have tracked the dynamic process at the single particle level. These results provide new insight into the design of more effective and selective imaging probes as well as drug carriers.