Studies on the Subcellular Trafficking of PAMAM Dendrimer
P.S. Lai, M.J. Shieh, C.L. Pai, C.Y. Wang and P.J. Lou
National Taiwan University, TW
dendrimer, intracellular trafficking
Polyamidoamine (PAMAM) dendrimers are a new class of highly branched spherical polymers and have emerged as a novel synthetic drug and gene carrier. However, the fate of the dendrimer-nucleotide complexes in a biological environment and the mechanism of dendrimer-mediated cellular uptake of oligonucleotides have not been fully clarified. The aim of this study is to elucidate the intracellular trafficking and subcellular distribution of generation 4 PAMAM dendrimers (G4). We tackled this issue by conjugating G4 with fluorescein isothiocyanate (FITC) and using organelle-selective dyes for double-staining confocal microscopy studies. We have, for the first time, delineated the detailed subcellular distribution and intracellular trafficking of PAMAM dendrimer using time-course studies. The most striking finding is that although G4-FITC was endocytosed following the endosome/lysosome pathway, certain amounts of the dendrimers shuttled between lysosomes and mitochondria at later time points. Small amount of the G4-FITC was observed in the Golgi apparatus, also at later time points, but there was no endoplasmic reticulum (ER) or nuclear localization of the dendrimers. The results of this study have provided us more information in basic cell biology related to PAMAM dendrimers, consequently, will lead to the further development of more precise PAMAM-drug or –gene delivery systems.
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Nanotech 2005 Conference Program Abstract