title: Influence of anchoring ligands and particle size on the colloidal stability and in vivo biodistribution of polyethylene glycol-coated gold nanoparticles in tumor-xenografted mice.
abstract: Polyethylene glycol (PEG)-coated (pegylated) gold nanoparticles (AuNPs) have been proposed as drug carriers and diagnostic contrast agents. However, the impact of particle characteristics on the biodistribution and pharmacokinetics of pegylated AuNPs is not clear. We investigated the effects of PEG molecular weight, type of anchoring ligand, and particle size on the assembly properties and colloidal stability of PEG-coated AuNPs. The pharmacokinetics and biodistribution of the most stable PEG-coated AuNPs in nude mice bearing subcutaneous A431 squamous tumors were further studied using (111)In-labeled AuNPs. AuNPs coated with thioctic acid (TA)-anchored PEG exhibited higher colloidal stability in phosphate-buffered saline in the presence of dithiothreitol than did AuNPs coated with monothiol-anchored PEG. AuNPs coated with high-molecular-weight (5000 Da) PEG were more stable than AuNPs coated with low-molecular-weight (2000 Da) PEG. Of the 20-nm, 40-nm, and 80-nm AuNPs coated with TA-terminated PEG(5000), the 20-nm AuNPs exhibited the lowest uptake by reticuloendothelial cells and the slowest clearance from the body. Moreover, the 20-nm AuNPs coated with TA-terminated PEG(5000) showed significantly higher tumor uptake and extravasation from the tumor blood vessels than did the 40- and 80-nm AuNPs. Thus, 20-nm AuNPs coated with TA-terminated PEG(5000) are promising potential drug delivery vehicles and diagnostic imaging agents.
authors.affiliation: Department of Experimental Diagnostic Imaging, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Guodong
authors.initials: G
authors.lastname: Zhang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Qian
authors.initials: Q
authors.lastname: Huang
authors.forename: Mei
authors.initials: M
authors.lastname: Tian
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Dong
authors.initials: D
authors.lastname: Liang
authors.forename: Chun
authors.initials: C
authors.lastname: Li
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007204:Indium / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D053768:Metal Nanoparticles / Q000737:chemistry*; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation / Q000379:methods*; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000494:pharmacology; D011897:Random Allocation; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D008063:Thioctic Acid / Q000737:chemistry; D014018:Tissue Distribution / Q000187:drug effects; D014183:Transplantation, Heterologous / Q000379:methods*
chemical_list: D007204:Indium; D011092:Polyethylene Glycols; D008063:Thioctic Acid; D006046:Gold