title: Prevention of carbon nanohorn agglomeration using a conjugate composed of comb-shaped polyethylene glycol and a peptide aptamer.
abstract: Assured dispersibility is a prerequisite for clinical application of nanomaterials. Carbon nanomaterials have hydrophobic surfaces and thus readily agglomerate under aqueous conditions. Various conjugates composed of a carbon surface-binding moiety and polyethylene glycol (PEG) have been examined as dispersants for carbon nanomaterials. Here we synthesized a conjugate composed of a comb-shaped PEG (cPEG) and carbon nanomaterial-binding peptide (NHBP-1). The resultant cPEG-NHBP3 conjugate displayed multiple units (2.4 on average) of NHBP-1 on a single cPEG molecule whose average molecular weight was 15-20 kDa. cPEG-NHBP3 endowed single-walled carbon nanohorns (SWNHs) with good dispersibility in vitro, which could not be achieved with 20PEG-NHBP, a conjugate composed of linear 20 kDa PEG and a single NHBP-1 peptide. Notably, cPEG-NHBP1, which was similar to 20PEG-NHBP but had a comb-shaped PEG backbone, functioned better as a dispersant than 20PEG-NHBP, suggesting a graft-type PEG formula is better-suited for dispersing nanomaterials. Finally, cPEG-NHBP3 treatment substantially suppressed formation of SWNH agglomerates in mouse lung, suggesting the potential utility of SWNHs as a carrier in drug delivery systems.
authors.affiliation: Department of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research, 3-10-6 Ariake, Koto-ku, Tokyo 135-8550, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Matsumura
authors.forename: Shigeo
authors.initials: S
authors.lastname: Sato
authors.forename: Masako
authors.initials: M
authors.lastname: Yudasaka
authors.forename: Akihiro
authors.initials: A
authors.lastname: Tomida
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsuruo
authors.forename: Sumio
authors.initials: S
authors.lastname: Iijima
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Shiba
mesh_terms: D000818:Animals; D052158:Aptamers, Peptide / Q000737:chemistry* / Q000493:pharmacokinetics; D002244:Carbon / Q000737:chemistry* / Q000493:pharmacokinetics; D005260:Female; D008168:Lung / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D049329:Nanostructures / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000493:pharmacokinetics
chemical_list: D052158:Aptamers, Peptide; D011092:Polyethylene Glycols; D002244:Carbon