title: Preparation and characterization of superparamagnetic iron oxide nanoparticles stabilized by alginate.
abstract: SPION with appropriate surface chemistry have been widely used experimentally for numerous in vivo applications. In this study, SPION stabilized by alginate (SPION-alginate) were prepared by a modified coprecipitation method. The structure, size, morphology, magnetic property and relaxivity of the SPION-alginate were characterized systematically by means of XRD, TEM, ESEM, AFM, DLS, SQUID magnetometer and MRI, respectively, and the interaction between alginate and iron oxide (Fe(3)O(4)) was characterized by FT-IR and AFM. The results revealed that typical iron oxide nanoparticles were Fe(3)O(4) with a core diameter of 5-10 nm and SPION-alginate had a hydrodynamic diameter of 193.8-483.2 nm. From the magnetization curve, the Ms of a suspension of SPION-alginate was 40 emu/g, corresponding to 73% of that of solid SPION-alginate. This high Ms may be due to the binding of Fe(3)O(4) nanoparticles to alginate macromolecule strands as visually confirmed by AFM. SPION-alginate of several hundred nanometers was stable in size for 12 months at 4 degrees C. Moreover, T1 relaxivity and T2 relaxivity of SPION-alginate in saline (1.5 T, 20 degrees C) were 7.86+/-0.20 s(-1) mM(-1) and 281.2+/-26.4 s(-1) mM(-1), respectively.
authors.affiliation: Department of Pharmaceutics, School of Pharmaceutical Sciences, Peking University, Beijing 100083, China.
authors.forename: Hui-li
authors.initials: HL
authors.lastname: Ma
authors.forename: Xian-rong
authors.initials: XR
authors.lastname: Qi
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Maitani
authors.forename: Tsuneji
authors.initials: T
authors.lastname: Nagai
mesh_terms: D000464:Alginates / Q000737:chemistry*; D003287:Contrast Media / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D005290:Ferric Compounds / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics; D053768:Metal Nanoparticles; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D012542:Scattering, Radiation; D017550:Spectroscopy, Fourier Transform Infrared; D013678:Technology, Pharmaceutical
chemical_list: D000464:Alginates; D003287:Contrast Media; D005290:Ferric Compounds; D006603:Hexuronic Acids; C000499:ferric oxide; D020723:Glucuronic Acid