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. 2014 Aug 26;7(2):131–151. doi: 10.1002/wnan.1281

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© 2014 The Authors. WIREs Nanomedicine and Nanobiotechnology published by Wiley Periodicals, Inc.

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

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Cellular delivery featuring quantum dots (QDs) in a combinatorial role. (a) QD scaffold for antisense oligonucleotide delivery and tracking. The 625 nm-emitting QDs (red) appended with antisense oligos for knockdown of folate receptor expression and cell uptake peptides (peptide p160) are released from the endosomes of MCF-7 cells after internalization. Endosomes were labeled with fluorescein-conjugated transferrin. Yellow coloring shows QDs colocalized with the green transferrin marker while red signal shows QDs liberated from endosomes to the cytosol. Left panel, bright field; right panel, fluorescence. (Reprinted with permission from Ref 93. Copyright 2013 Wiley) Scale bar is 5 µm. (b) Drug and small interfering RNA (siRNA) delivery mediated by QDs. Confocal images of HeLa cells ∼6 h after loading with QD-β-CD-CPP complexes carrying MDR1-directed siRNA and doxorubicin (Dox). Cells loaded with MDR1-directed siRNA showed higher intracellular levels of Dox compared to #siRNA(−) cells. Scale bar, 40 µm. β-CD is β-cyclodextrin. (Reprinted with permission from Ref 94. Copyright 2012 Elsevier) (c) Combinatorial QD delivery for spatiotemporal cell labeling. Multiple colors of QDs were delivered to the cytosol by (yellow), early endosomes (red), late endosomes (green), and the plasma membrane (magenta) using microinjection, peptide- and polymer-mediated delivery. Nucleus is stained blue (DAPI). (Reprinted with permission from Ref 27. Copyright 2011 ACS) Scale bar is 5 µm. (d) Supported bilayer system for simultaneous delivery of multiple imaging and therapeutic cargos. Nanoporous silica cores (labeled with AlexaFluor 532, yellow) were loaded with four model cargos: calcein (green), Alexa Fluor 647-labeled dsDNA oligonucleotide (magenta), RFP (orange), and CdSe/ZnS QDs (teal). Hep3B cells (labeled with CellTracker Violet (cytosol, purple) and Hoechst 33342 (nuclei, purple) 4 h after initial delivery display the distribution of cargos to respective, targeted locations. (Reprinted with permission from Ref 95. Copyright 2013 Macmillan Publishers Ltd) Scale bar, 20 µm.