title: Simple PEG conjugation of SPIO via an Au-S bond improves its tumor targeting potency as a novel MR tumor imaging agent.
abstract: Gold/iron oxide magnetic nanoparticles are hybrid nanoparticles containing a core of magnetic iron oxide and surface colloidal gold, which allows for various biomaterials to be immobilized on the surface of the iron oxide nanoparticles via colloidal gold. Here, we developed a novel magnetic resonance (MR) imaging agent to broaden the MR tumor-imaging spectrum of superparamagnetic iron oxide nanoparticles (SPIO), e.g., Feridex(), a clinical MR imaging agent for diagnosing liver cancer. Au/Feridex was synthesized by electron beam irradiation, and thiol-modified poly(ethylene glycol) (PEG-SH) was easily conjugated to its surface via an Au-S bond without the need for any chemical reactions. PEG conjugation of Au/Feridex enhanced its accumulation in Meth-A tumor tissue and decreased its accumulation in normal liver tissue. In addition, MRI using PEG-Au/Feridex, in contrast to MRI using unmodified Au/Feridex and Feridex, detected B16BL6 and Meth-A tumor tissues in vivo. This finding indicates that PEG-Au/Feridex is useful for diagnosing various types of tumors. In addition, because the synthesis of PEG-Au/Feridex is simple and high yields are easily produced, PEG-modified SPIO for tumor diagnosis can be prepared on an industrial scale with low cost.
authors.affiliation: Center for Advanced Medical Engineering and Informatics, Osaka University, Suita, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kojima
authors.forename: Yohei
authors.initials: Y
authors.lastname: Mukai
authors.forename: Mai
authors.initials: M
authors.lastname: Yoshikawa
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Kamei
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Masahito
authors.initials: M
authors.lastname: Morita
authors.forename: Toshiro
authors.initials: T
authors.lastname: Inubushi
authors.forename: Takao A
authors.initials: TA
authors.lastname: Yamamoto
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yoshioka
authors.forename: Naoki
authors.initials: N
authors.lastname: Okada
authors.forename: Satoshi
authors.initials: S
authors.lastname: Seino
authors.forename: Shinsaku
authors.initials: S
authors.lastname: Nakagawa
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003911:Dextrans; D005290:Ferric Compounds / Q000737:chemistry; D052203:Ferrosoferric Oxide / Q000737:chemistry* / Q000493:pharmacokinetics; D006046:Gold / Q000737:chemistry* / Q000493:pharmacokinetics; D008113:Liver Neoplasms / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D008545:Melanoma / Q000473:pathology; D053768:Metal Nanoparticles / Q000737:chemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D046529:Microscopy, Electron, Transmission; D009369:Neoplasms / Q000473:pathology*; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000493:pharmacokinetics; D013455:Sulfur / Q000737:chemistry*
chemical_list: D003911:Dextrans; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; C000499:ferric oxide; D011092:Polyethylene Glycols; D013455:Sulfur; D006046:Gold; C065507:ferumoxides; D052203:Ferrosoferric Oxide