title: Cellular uptake and fate of PEGylated gold nanoparticles is dependent on both cell-penetration peptides and particle size.
abstract: Numerous studies have examined how the cellular delivery of gold nanoparticles (AuNPs) is influenced by different physical and chemical characteristics; however, the complex relationship between AuNP size, uptake efficiency and intracellular localization remains only partially understood. Here we examine the cellular uptake of a series of AuNPs ranging in diameter from 2.4 to 89 nm that are synthesized and made soluble with poly(ethylene glycol)-functionalized dithiolane ligands terminating in either carboxyl or methoxy groups and covalently conjugated to cell penetrating peptides. Following synthesis, extensive physical characterization of the AuNPs was performed with UV-vis absorption, gel electrophoresis, zeta potential, dynamic light scattering, and high resolution transmission electron microscopy. Uptake efficiency and intracellular localization of the AuNP-peptide conjugates in a model COS-1 cell line were probed with a combination of silver staining, fluorescent counterstaining, and dual mode fluorescence coupled to nonfluorescent scattering. Our findings show that AuNP cellular uptake is directly dependent on the surface display of the cell-penetrating peptide and that the ultimate intracellular destination is further determined by AuNP diameter. The smallest 2.4 nm AuNPs were found to localize in the nucleus, while intermediate 5.5 and 8.2 nm particles were partially delivered into the cytoplasm, showing a primarily perinuclear fate along with a portion of the nanoparticles appearing to remain at the membrane. The 16 nm and larger AuNPs did not enter the cells and were located at the cellular periphery. A preliminary assessment of cytotoxicity demonstrated minimal effects on cellular viability following peptide-mediated uptake.
authors.affiliation: Optical Sciences Division, Code 5611, U.S. Naval Research Laboratory, Washington, DC 20375, USA. Eunkeuoh@ccs.nrl.navy.mil
authors.forename: Eunkeu
authors.initials: E
authors.lastname: Oh
authors.forename: James B
authors.initials: JB
authors.lastname: Delehanty
authors.forename: Kim E
authors.initials: KE
authors.lastname: Sapsford
authors.forename: Kimihiro
authors.initials: K
authors.lastname: Susumu
authors.forename: Ramasis
authors.initials: R
authors.lastname: Goswami
authors.forename: Juan B
authors.initials: JB
authors.lastname: Blanco-Canosa
authors.forename: Philip E
authors.initials: PE
authors.lastname: Dawson
authors.forename: Jessica
authors.initials: J
authors.lastname: Granek
authors.forename: Megan
authors.initials: M
authors.lastname: Shoff
authors.forename: Qin
authors.initials: Q
authors.lastname: Zhang
authors.forename: Peter L
authors.initials: PL
authors.lastname: Goering
authors.forename: Alan
authors.initials: A
authors.lastname: Huston
authors.forename: Igor L
authors.initials: IL
authors.lastname: Medintz
mesh_terms: D000818:Animals; D001692:Biological Transport; D019556:COS Cells; D002470:Cell Survival / Q000187:drug effects; D057846:Cell-Penetrating Peptides / Q000737:chemistry* / Q000378:metabolism*; D002522:Chlorocebus aethiops; D004305:Dose-Response Relationship, Drug; D006046:Gold / Q000737:chemistry* / Q000378:metabolism* / Q000633:toxicity; D042541:Intracellular Space / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D057846:Cell-Penetrating Peptides; D011092:Polyethylene Glycols; D006046:Gold