title: Intracellular delivery of quantum dot-protein cargos mediated by cell penetrating peptides.
abstract: We utilize cell penetrating peptide functionalized QDs as specific vectors for the intracellular delivery of model fluorescent protein cargos. Multiple copies of two structurally diverse fluorescent proteins, the 27 kDa monomeric yellow fluorescent protein and the 240 kDa multichromophore b-phycoerythrin complex, were attached to QDs using either metal-affinity driven self-assembly or biotin-Streptavidin binding, respectively. Cellular uptake of these complexes was found to depend on the additional presence of cell-penetrating peptides within the QD-protein conjugates. Once inside the cells, the QD conjugates were mostly distributed within endolysosomal compartments, indicating that intracellular delivery of both QD assemblies was primarily driven by endocytotic uptake. Cellular microinjection of QD-fluorescent protein assemblies was also utilized as an alternate delivery strategy that could bypass the endocytic pathway. Simultaneous signals from both the QDs and the fluorescent proteins allowed verification of their colocalization and conjugate integrity upon delivery inside live cells. Due to their intrinsic fluorescence properties, this class of proteins provides a unique tool to test the ability of QDs functionalized with cell penetrating peptides to mediate the intracellular delivery of both small and large size protein cargos. Use of QD-peptide/fluorescent protein vectors may make powerful tools for understanding the mechanisms of nanoparticle-mediated drug delivery.
authors.affiliation: Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, DC 20375, USA. igor.medintz@nrl.navy.mil
authors.forename: Igor L
authors.initials: IL
authors.lastname: Medintz
authors.forename: Thomas
authors.initials: T
authors.lastname: Pons
authors.forename: James B
authors.initials: JB
authors.lastname: Delehanty
authors.forename: Kimihiro
authors.initials: K
authors.lastname: Susumu
authors.forename: Florence M
authors.initials: FM
authors.lastname: Brunel
authors.forename: Philip E
authors.initials: PE
authors.lastname: Dawson
authors.forename: Hedi
authors.initials: H
authors.lastname: Mattoussi
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D002460:Cell Line; D004587:Electrophoresis, Agar Gel; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D042541:Intracellular Space / Q000737:chemistry / Q000378:metabolism; D008164:Luminescent Proteins / Q000737:chemistry* / Q000378:metabolism; D008970:Molecular Weight; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D045663:Quantum Dots
chemical_list: D008164:Luminescent Proteins; D010455:Peptides