title: Circulation and long-term fate of functionalized, biocompatible single-walled carbon nanotubes in mice probed by Raman spectroscopy.
abstract: Carbon nanotubes are promising new materials for molecular delivery in biological systems. The long-term fate of nanotubes intravenously injected into animals in vivo is currently unknown, an issue critical to potential clinical applications of these materials. Here, using the intrinsic Raman spectroscopic signatures of single-walled carbon nanotubes (SWNTs), we measured the blood circulation of intravenously injected SWNTs and detect SWNTs in various organs and tissues of mice ex vivo over a period of three months. Functionalization of SWNTs by branched polyethylene-glycol (PEG) chains was developed, enabling thus far the longest SWNT blood circulation up to 1 day, relatively low uptake in the reticuloendothelial system (RES), and near-complete clearance from the main organs in approximately 2 months. Raman spectroscopy detected SWNT in the intestine, feces, kidney, and bladder of mice, suggesting excretion and clearance of SWNTs from mice via the biliary and renal pathways. No toxic side effect of SWNTs to mice was observed in necropsy, histology, and blood chemistry measurements. These findings pave the way to future biomedical applications of carbon nanotubes.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
authors.forename: Zhuang
authors.initials: Z
authors.lastname: Liu
authors.forename: Corrine
authors.initials: C
authors.lastname: Davis
authors.forename: Weibo
authors.initials: W
authors.lastname: Cai
authors.forename: Lina
authors.initials: L
authors.lastname: He
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Chen
authors.forename: Hongjie
authors.initials: H
authors.lastname: Dai
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000032:analysis / Q000493:pharmacokinetics* / Q000633:toxicity*; D001775:Blood Circulation; D007275:Injections, Intravenous; D008422:Materials Testing; D051379:Mice; D008815:Mice, Inbred Strains; D037742:Nanotubes, Carbon / Q000032:analysis / Q000633:toxicity*; D011092:Polyethylene Glycols / Q000737:chemistry / Q000493:pharmacokinetics / Q000633:toxicity; D013059:Spectrum Analysis, Raman; D014018:Tissue Distribution
chemical_list: D001672:Biocompatible Materials; D037742:Nanotubes, Carbon; D011092:Polyethylene Glycols