title: Gastrointestinal bioavailability of 2.0 nm diameter gold nanoparticles.
abstract: The use of gold nanoparticles as imaging agents and therapeutic delivery systems is growing rapidly. However, a significant limitation of gold nanoparticles currently is their low absorption efficiencies in the gastrointestinal (GI) tract following oral administration. In an attempt to identify ligands that facilitate gold nanoparticle absorption in the GI tract, we have studied the oral bioavailability of 2.0 nm diameter gold nanoparticles modified with the small molecules p-mercaptobenzoic acid and glutathione, and polyethylene glycols (PEG) of different lengths and charge (neutral and anionic). We show that GI absorption of gold nanoparticles modified with the small molecules tested was undetectable. However, the absorption of PEGs depended upon PEG length, with the shortest PEG studied yielding gold nanoparticle absorptions that are orders-of-magnitude larger than observed previously. As the oral route is the most convenient one for administering drugs and diagnostic reagents, these results suggest that short-chain PEGs may be useful in the design of gold nanoparticles for the diagnosis and treatment of disease.
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States.
authors.forename: Candice A
authors.initials: CA
authors.lastname: Smith
authors.forename: Carrie A
authors.initials: CA
authors.lastname: Simpson
authors.forename: Ganghyeok
authors.initials: G
authors.lastname: Kim
authors.forename: Carly J
authors.initials: CJ
authors.lastname: Carter
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Feldheim
mesh_terms: D000818:Animals; D001682:Biological Availability; D005260:Female; D041981:Gastrointestinal Tract / Q000378:metabolism*; D005978:Glutathione / Q000737:chemistry; D006046:Gold / Q000737:chemistry* / Q000493:pharmacokinetics*; D008626:Mercuribenzoates / Q000737:chemistry; D053768:Metal Nanoparticles; D051379:Mice; D008807:Mice, Inbred BALB C; D008958:Models, Molecular; D008968:Molecular Conformation; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry
chemical_list: C043407:4-mercuribenzoate; D008626:Mercuribenzoates; D011092:Polyethylene Glycols; D006046:Gold; D005978:Glutathione