title: Paramagnetic ultrasmall gadolinium oxide nanoparticles as advanced T1 MRI contrast agent: account for large longitudinal relaxivity, optimal particle diameter, and in vivo T1 MR images.
abstract: Paramagnetic ultrasmall gadolinium oxide (Gd(2)O(3)) nanoparticles with particle diameters (d) of approximately 1 nm were synthesized by using three kinds of Gd(III) ion precursors and by refluxing each of them in tripropylene glycol under an O(2) flow. A large longitudinal relaxivity (r(1)) of water proton of 9.9 s(-1) mM(-1) was estimated. As a result, high contrast in vivo T(1) MR images of the brain tumor of a rat were observed. This large r(1) is discussed in terms of the huge surface to volume ratio (S/V) of the ultrasmall gadolinium oxide nanoparticles coupled with the cooperative induction of surface Gd(III) ions for the longitudinal relaxation of a water proton. It is found from the d dependence of r(1) that the optimal range of d for the maximal r(1), which may be used as an advanced T(1) MRI contrast agent, is 1-2.5 nm.
authors.affiliation: Department of Chemistry, College of Natural Sciences, Kyungpook National University, Taegu, South Korea.
authors.forename: Ja Young
authors.initials: JY
authors.lastname: Park
authors.forename: Myung Ju
authors.initials: MJ
authors.lastname: Baek
authors.forename: Eun Sook
authors.initials: ES
authors.lastname: Choi
authors.forename: Seungtae
authors.initials: S
authors.lastname: Woo
authors.forename: Joo Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Tae Jeong
authors.initials: TJ
authors.lastname: Kim
authors.forename: Jae Chang
authors.initials: JC
authors.lastname: Jung
authors.forename: Kwon Seok
authors.initials: KS
authors.lastname: Chae
authors.forename: Yongmin
authors.initials: Y
authors.lastname: Chang
authors.forename: Gang Ho
authors.initials: GH
authors.lastname: Lee
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000175:diagnosis; D045744:Cell Line, Tumor; D003287:Contrast Media / Q000008:administration & dosage / Q000737:chemistry* / Q000633:toxicity; D005682:Gadolinium / Q000008:administration & dosage / Q000737:chemistry* / Q000633:toxicity; D020723:Glucuronic Acid / Q000737:chemistry; D006801:Humans; D007267:Injections; D008279:Magnetic Resonance Imaging; D008280:Magnetics; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011522:Protons; D051381:Rats; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013818:Thermogravimetry; D014867:Water / Q000737:chemistry
chemical_list: D003287:Contrast Media; D011522:Protons; D014867:Water; C030581:gadolinium oxide; D020723:Glucuronic Acid; D005682:Gadolinium