title: Neuronal uptake and intracellular superoxide scavenging of a fullerene (C60)-poly(2-oxazoline)s nanoformulation.
abstract: Fullerene, the third allotrope of carbon, has been referred to as a "radical sponge" because of its powerful radical scavenging activities. However, the hydrophobicity and toxicity associated with fullerene limits its application as a therapeutic antioxidant. In the present study, we sought to overcome these limitations by generating water-soluble nanoformulations of fullerene (C(60)). Fullerene (C(60)) was formulated with poly(N-vinyl pyrrolidine) (PVP) or poly(2-alkyl-2-oxazoline)s (POx) homopolymer and random copolymer to form nano-complexes. These C(60)-polymer complexes were characterized by UV-vis spectroscopy, infrared spectroscopy (IR), dynamic light scattering (DLS), atomic force microscopy (AFM) and transmission electron microscopy (TEM). Cellular uptake and intracellular distribution of the selected formulations in catecholaminergic (CATH.a) neurons were examined by UV-vis spectroscopy, immunofluorescence and immunogold labeling. Electron paramagnetic resonance (EPR) spectroscopy was used to determine the ability of these C(60)-polymer complexes to scavenge superoxide. Their cytotoxicity was evaluated in three different cell lines. C(60)-POx and C(60)-PVP complexes exhibited similar physicochemical properties and antioxidant activities. C(60)-poly(2-ethyl-2-oxazoline) (PEtOx) complex, but not C(60)-PVP complex, were efficiently taken up by CATH.a neurons and attenuated the increase in intra-neuronal superoxide induced by angiotensin II (Ang II) stimulation. These results show that C(60)-POx complexes are non-toxic, neuronal cell permeable, superoxide scavenging antioxidants that might be promising candidates for the treatment of brain-related diseases associated with increased levels of superoxide.
authors.affiliation: Center for Drug Delivery and Nanomedicine, University of Nebraska Medical Center, Omaha, NE 68198, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Tong
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Zimmerman
authors.forename: Shumin
authors.initials: S
authors.lastname: Li
authors.forename: Xiang
authors.initials: X
authors.lastname: Yi
authors.forename: Robert
authors.initials: R
authors.lastname: Luxenhofer
authors.forename: Rainer
authors.initials: R
authors.lastname: Jordan
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Kabanov
mesh_terms: D000818:Animals; D002460:Cell Line; D004285:Dogs; D004578:Electron Spin Resonance Spectroscopy; D037741:Fullerenes / Q000737:chemistry*; D006801:Humans; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D058726:Nanoconjugates / Q000008:administration & dosage / Q000737:chemistry* / Q000648:ultrastructure; D009474:Neurons / Q000378:metabolism*; D010080:Oxazoles / Q000737:chemistry*; D011073:Polyamines; D011108:Polymers / Q000737:chemistry*; D011145:Polyvinyls / Q000737:chemistry; D011759:Pyrrolidines / Q000737:chemistry; D013481:Superoxides / Q000378:metabolism*
chemical_list: D037741:Fullerenes; D058726:Nanoconjugates; D010080:Oxazoles; D011073:Polyamines; D011108:Polymers; D011145:Polyvinyls; D011759:Pyrrolidines; C511916:poly(2-ethyl-2-oxazoline); C505150:poly(N-vinylpyrrolidine); D013481:Superoxides