Super-resolution imaging reveals the subcellular distribution of dextran at the nanoscale in living cells

Theranostic visualization of dextran at the nanoscale is beneficial for understanding the bioregulatory mechanisms of this molecule. In this study, we applied structured illumination microscopy (SIM) to capture the distribution of Cy5-Dextran at different incubation periods in living cells. The results showed that Cy5-Dextran could be absorbed by HeLa cells. In addition, we clarified that Cy5-Dextran exhibited differential organelle distribution (lysosomal or mitochondrial) in a time-dependent manner. Moreover, lysosomal Cy5-Dextran localization was found to be independent of the autophagy process, while Cy5-Dextran localized to the mitochondria triggered a pro-apoptotic event, upregulating the levels of reactive oxygen species (ROS) to accelerate mitochondrial fragmentation. This work uses a visualized strategy to reveal the anti-tumor bioactivity of dextran, which was achieved by regulating apoptosis and autophagy.