title: Facile synthesis of ultrasmall PEGylated iron oxide nanoparticles for dual-contrast T1- and T2-weighted magnetic resonance imaging.
abstract: The development of new types of high-performance nanoparticulate MR contrast agents with either positive (T(1)) or dual-contrast (both positive and negative, T(1) + T(2)) ability is of great importance. Here we report a facile synthesis of ultrasmall PEGylated iron oxide nanoparticles for dual-contrast T(1)- and T(2)-weighted MRI. The produced superparamagnetic iron oxide nanoparticles (SPIONs) are of high crystallinity and size uniformity with an average diameter of 5.4 nm, and can be individually dispersed in the physiological buffer with high stability. The SPIONs reveal an impressive saturation magnetization of 94 emu g(-1) Fe(3)O(4), the highest r(1) of 19.7 mM(-1) s(-1) and the lowest r(2)/r(1) ratio of 2.0 at 1.5 T reported so far for PEGylated iron oxide nanoparticles. T(1)- and T(2)-weighted MR images showed that the SPIONs could not only improve surrounding water proton signals in the T(1)-weighted image, but induce significant signal reduction in the T(2)-weighted image. The good contrast effect of the SPIONs as T(1) + T(2) dual-contrast agents might be due to its high magnetization, optimal nanoparticle size for T(1) + T(2) dual-contrast agents, high size monodispersity and excellent colloidal stability. In vitro cell experiments showed that the SPIONs have little effect on HeLa cell viability.
authors.affiliation: College of Chemistry, Beijing Normal University, Beijing, People's Republic of China. fqhu@bnu.edu.cn
authors.forename: Fengqin
authors.initials: F
authors.lastname: Hu
authors.forename: Qiaojuan
authors.initials: Q
authors.lastname: Jia
authors.forename: Yilin
authors.initials: Y
authors.lastname: Li
authors.forename: Mingyuan
authors.initials: M
authors.lastname: Gao
mesh_terms: D002470:Cell Survival; D003287:Contrast Media / Q000138:chemical synthesis* / Q000737:chemistry; D005290:Ferric Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D008279:Magnetic Resonance Imaging; D008280:Magnetics; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; C000499:ferric oxide; D011092:Polyethylene Glycols