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

Abstract

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.

Guiding protein delivery into live cells using DNA-programmed membrane fusion

“… 10 Previous work has indicated that treating cells with endocytosis inhibitors could effectively inhibit various endocytotic pathways, for example, endocytic chlorpromazine (CPZ, interfering with clathrin-dependent endocytosis) 33 , 34 and methyl-β-cyclodextrin (MβCD, disrupting caveola-dependent endocytosis). 35 , 36 We also found that CPZ or methyl-β-cyclodextrin could reduce the cellular uptake of liposomes by L1210 and HeLa cells (Fig. S14 † ).…”

Highly hydrophilic carbon nanoparticles: uptake mechanism by mammalian and plant cells

“…The dose of each inhibitor was chosen according to previous studies. [23][24][25]33,34 Aer 2 h treatment with these inhibitors, the culture medium was removed, and fresh medium containing FCNPs (20 mg mL À1 ) was added to the cells, which were maintained for another 2 h. 21 Endocytosis inhibitors were incubated with BY-2 cells for 2 h. The inhibitors were 30 mM chlorpromazine, 20 mM methyl-b-cyclodextrin, 10 mM wortmannin, and 37 mM genistein. Cells were washed three times with PBS aer removing inhibitors by a cell strainer (40 mm).…”

“…Similar results have been published for other types of nanoparticles such as silicas and polymer dots. 23,44,45 We further investigated endocytic processes of FCNPs.…”

“…Cellular uptake has been studied with other types of nanoparticles. [21][22][23][24] For instance, graphene oxide (GO) has been reported to exhibit different mechanisms depending on the cell type, with a microtubule-dependent mechanism in Saos-2 osteoblasts, and clathrin-dependent in HepG2 hepatocytes and RAW-264.7 macrophages. 24 Nanoparticles were shown to be incorporated into the plasma membrane and enter cells through the following two different endocytosis pathways that depended on the particle size: phagocytosis (particles larger than 0.5 mm) and pinocytosis (uptake of uids and solutes).…”

Live‐cell imaging of octaarginine‐modified polymer dots via single particle tracking

“…Although Pdots can be ingested in large amount by macrophages rapidly, the amount and speed of Pdots uptake by epithelial cells are much more limited. Moreover, following endocytosis, majority of Pdots are transported and destined into lysosomes, implying that bioactive cargos, such as DNA, RNA and proteins, are unlikely to keep their intracellular functionality …”