Surface-Ligand-Dependent Cellular Interaction, Subcellular Localization, and Cytotoxicity of Polymer-Coated Quantum Dots

Abstract

Nanoparticle- and quantum-dot (QD)-based bioprobes are emerging as alternatives to small-molecule probes for in vitro and in vivo applications. However, their cellular interaction and cell uptake mechanism are significantly different from those of small-molecule probes and are extremely sensitive to surface ligands. These present a barrier in the development of nanoparticles and QDs as cellular probes. This work focused on the synthesis of various functionalized QDs with tunable surface charge, hydrophobicity, and functionalization with poly(ethylene glycol) (PEGylation) and their cellular interaction. We found that the surface functional groups of nanometer-sized probes significantly dictated their cellular interaction, subcellular localization, and cytotoxicity. A dose-dependent interaction was observed for all types of QDs, but the cationic surface charge or hydrophobicity would increase the cellular interaction as compared to the anionic surface charge. Cationic QDs rapidly entered cells and induced c...