title: Gd3N@C84(OH)x: a new egg-shaped metallofullerene magnetic resonance imaging contrast agent.
abstract: Water-soluble derivatives of gadolinium-containing metallofullerenes have been considered to be excellent candidates for new magnetic resonance imaging (MRI) contrast agents because of their high relaxivity and characteristic encapsulation of the lanthanide ions (Gd(3+)), preventing their release into the bioenvironment. The trimetallic nitride template endohedral metallofullerenes (TNT EMFs) have further advantages of high stability, high relative yield, and encapsulation of three Gd(3+) ions per molecule as illustrated by the previously reported nearly spherical, Gd3N@I(h)-C80. In this study, we report the preparation and functionalization of a lower-symmetry EMF, Gd3N@C(s)-C84, with a pentalene (fused pentagons) motif and an egg-shaped structure. The Gd3N@C84 derivative exhibits a higher (1)H MR relaxivity compared to that of the Gd3N@C80 derivative synthesized the same way, at low (0.47 T), medium (1.4 T), and high (9.4 T) magnetic fields. The Gd3N@C(s)-C84 derivative exhibits a higher hydroxyl content and aggregate size, as confirmed by X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS) experiments, which could be the main reasons for the higher relaxivity.
authors.affiliation: Virginia Tech Carilion Research Institute , Roanoke, VA, 24016, United States.
authors.forename: Jianyuan
authors.initials: J
authors.lastname: Zhang
authors.forename: Youqing
authors.initials: Y
authors.lastname: Ye
authors.forename: Ying
authors.initials: Y
authors.lastname: Chen
authors.forename: Christopher
authors.initials: C
authors.lastname: Pregot
authors.forename: Tinghui
authors.initials: T
authors.lastname: Li
authors.forename: Sharavanan
authors.initials: S
authors.lastname: Balasubramaniam
authors.forename: David B
authors.initials: DB
authors.lastname: Hobart
authors.forename: Yafen
authors.initials: Y
authors.lastname: Zhang
authors.forename: Sungsool
authors.initials: S
authors.lastname: Wi
authors.forename: Richey M
authors.initials: RM
authors.lastname: Davis
authors.forename: Louis A
authors.initials: LA
authors.lastname: Madsen
authors.forename: John R
authors.initials: JR
authors.lastname: Morris
authors.forename: Stephen M
authors.initials: SM
authors.lastname: LaConte
authors.forename: Gordon T
authors.initials: GT
authors.lastname: Yee
authors.forename: Harry C
authors.initials: HC
authors.lastname: Dorn
mesh_terms: D003287:Contrast Media / Q000737:chemistry*; D037741:Fullerenes / Q000737:chemistry*; D005682:Gadolinium / Q000737:chemistry*; D008279:Magnetic Resonance Imaging
chemical_list: D003287:Contrast Media; D037741:Fullerenes; D005682:Gadolinium