title: Facile preparation of zwitterion-stabilized superparamagnetic iron oxide nanoparticles (ZSPIONs) as an MR contrast agent for in vivo applications.
abstract: We describe a simple method for synthesizing superparamagnetic nanoparticles (SPIONs) as small, stable contrast agents for magnetic resonance imaging (MRI) based on sulfobetaine zwitterionic ligands. SPIONs synthesized by thermal decomposition were coated with zwitterions to impart water dispersibility and high in vivo stability through the nanoemulsion method. Zwitterion surfactant coating layers are formed easily on oleic acid-stabilized SPIONs via hydrophobic and van der Waals interactions. Our zwitterion-coated SPIONs (ZSPIONs) had ultrathin (∼5 nm) coating layers with mean sizes of 12.0 ± 2.5 nm, as measured by dynamic light scattering (DLS). Upon incubation in 1 M NaCl and 10% FBS, the ZSPIONs showed high colloidal stabilities without precipitating, as monitored by DLS. The T2 relaxivity coefficient of the ZSPIONs, obtained by measuring the relaxation rate on the basis of the iron concentration, was 261 mM(-1) s(-1). This value was much higher than that of the commercial T2 contrast agent because of the ultrathin coating layer. Furthermore, we confirmed that ZSPIONs can be used as MR contrast agents for in vivo applications such as tumor imaging and lymph node mapping.
authors.affiliation: Division of Magnetic Resonance Research, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883, Republic of Korea.
authors.forename: Dongkyu
authors.initials: D
authors.lastname: Kim
authors.forename: Min Kyung
authors.initials: MK
authors.lastname: Chae
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Joo
authors.forename: Il-ha
authors.initials: IH
authors.lastname: Jeong
authors.forename: Jee-Hyun
authors.initials: JH
authors.lastname: Cho
authors.forename: Chulhyun
authors.initials: C
authors.lastname: Lee
mesh_terms: D000818:Animals; D018827:Carcinoma, Lewis Lung / Q000175:diagnosis; D045744:Cell Line, Tumor; D003287:Contrast Media / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D059346:Magnets / Q000737:chemistry*; D051379:Mice; D008807:Mice, Inbred BALB C; D053758:Nanoparticles / Q000737:chemistry*; D019301:Oleic Acid / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; D013501:Surface-Active Agents; D014867:Water; C000499:ferric oxide; D019301:Oleic Acid