Protein Conjugation Helped CdTe Quantum Dots for the Specific Labeling and Super-Resolution Imaging of Lysosomes

Semiconductor quantum dots possess many attractive features such as high quantum yield, and narrow emission, and offer great advantages over organic dyes. However, the fluorescence intermittency and the cytotoxicity limit their biological applications. In this communication, we show a substantial increase in cell viability and the tuning of intermittency of water-soluble CdTe quantum dots upon conjugation with bovine serum albumin (BSA), which helped them for their use as fluorescent probe for super resolution bioimaging of lysosomes. The quantum dots were not only found to be highly specific to stain the lysosome but also provided the super-resolution image's resolution down to similar to 60 nm, which is close to the smallest size of the lysosome. Photons per cycle were found to play a significant role in improving localization precision and thus improved the quality of the super resolution images.