Semiconductor quantum dots (QDs) have recently been used to deliver and monitor biomolecules, such as drugs and proteins. However, QDs alone have a low efficiency of transport across the plasma membrane. In order to increase the efficiency, we used synthetic nona-arginine (SR9), a cell-penetrating peptide, to facilitate uptake. We found that SR9 increased the cellular uptake of QDs in a noncovalent binding manner between QDs and SR9. Further, we investigated mechanisms of QD/SR9 cellular internalization. Low temperature and metabolic inhibitors markedly inhibited the uptake of QD/SR9, indicating that internalization is an energy-dependent process. Results from both the pathway inhibitors and the RNA interference (RNAi) technique suggest that cellular uptake of QD/SR9 is predominantly a lipid raft-dependent process mediated by macropinocytosis. However, involvement of clathrin and caveolin-1 proteins in transducing QD/SR9 across the membrane cannot be completely ruled out. Copyright © 2010 Yi Xu et al.


Biological Sciences

Second Department


Keywords and Phrases

Arginine Derivative; Caveolin 1; Cell Penetrating Peptide; Clathrin; Nona Arginine; Quantum Dot; Unclassified Drug; Cadmium Derivative; Cadmium Selenide; Caveolin; Clathrin Heavy Chain; Nonaarginine; Oligopeptide; Selenium Derivative; Small Interfering RNA; Sulfide; Zinc Derivative; Zinc Sulfide; Cell Membrane; Cell Metabolism; Controlled Study; Energy; Human; Human Cell; Inhibition Kinetics; Internalization; Lipid Raft; Low Temperature; RNA Interference; Signal Transduction; Drug Antagonism; Drug Delivery System; Fluorescence Microscopy; Genetics; Metabolism; Methodology; Pinocytosis; Transport At the Cellular Level; Tumor Cell Line; Western Blotting; Biological Transport; Blotting, Western; Cadmium Compounds; Caveolins; Cell Line, Tumor; Clathrin Heavy Chains; Drug Delivery Systems; Humans; Microscopy, Fluorescence; Oligopeptides; Pinocytosis; Quantum Dots; RNA, Small Interfering; Selenium Compounds; Sulfides; Zinc Compounds

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