title: A high poly(ethylene glycol) density on graphene nanomaterials reduces the detachment of lipid-poly(ethylene glycol) and macrophage uptake.
abstract: Amphiphilic lipid-poly(ethylene glycol) (LPEG) is widely used for the noncovalent functionalization of graphene nanomaterials (GNMs) to improve their dispersion in aqueous solutions for biomedical applications. However, not much is known about the detachment of LPEGs from GNMs and macrophage uptake of dispersed GNMs in relation to the alkyl chain coverage, the PEG coverage, and the linker group in LPEGs. In this study we examined these relationships using single walled carbon nanohorns (SWCNHs). The high coverage of PEG rather than that of alkyl chains was dominant in suppressing the detachment of LPEGs from SWCNHs in protein-containing physiological solution. Correspondingly, the quantity of LPEG-covered SWCNHs (LPEG-SWCNHs) taken up by macrophages decreased at a high PEG coverage. Our study also demonstrated an effect of the ionic group in LPEG on SWCNH uptake into macrophages. A phosphate anionic group in the LPEG induced lower alkyl chain coverage and easy detachment of the LPEG, however, the negative surface charge of LPEG-SWCNHs reduced the uptake of SWCNHs by macrophages.
authors.affiliation: Department of Material Science and Engineering, Meijo University, Tenpaku, Nagoya 468-8502, Japan.
authors.forename: Mei
authors.initials: M
authors.lastname: Yang
authors.forename: Momoyo
authors.initials: M
authors.lastname: Wada
authors.forename: Minfang
authors.initials: M
authors.lastname: Zhang
authors.forename: Kostas
authors.initials: K
authors.lastname: Kostarelos
authors.forename: Ryota
authors.initials: R
authors.lastname: Yuge
authors.forename: Sumio
authors.initials: S
authors.lastname: Iijima
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Masuda
authors.forename: Masako
authors.initials: M
authors.lastname: Yudasaka
mesh_terms: D000818:Animals; D006108:Graphite / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry*; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000378:metabolism
chemical_list: D008055:Lipids; D011092:Polyethylene Glycols; D006108:Graphite