title: Novel Positive-Charged Nanoparticles for Efficient Magnetic Resonance Imaging of Islet Transplantation.
abstract: Significant graft loss immediately after islet transplantation occurs due to immunological and nonimmunological events. Magnetic resonance imaging (MRI) is an attractive potential tool for monitoring islet mass in vivo. Although an efficient uptake of MRI contrast agent is required for islet cell labeling, commercially available magnetic nanoparticles are not efficiently transduced into cells. In this study, we developed six kinds of novel magnetic iron oxide nanoparticles, which are electrically charged by cationic end-group substitution of dextran. Each of the nanoparticles consisted of a small monocrystalline, superparamagnetic iron oxide core that is stabilized by a cross-linked aminated dextran coating to improve stability. We also used three different commercially available nanoparticles for controls. The labeling efficiency of the novel nanoparticles was evaluated, and the feasibility of the imaging by MRI was assessed. The positive-charged nanoparticles were transduced into a β-cell line, MIN6 cells, but not three commercially available nanoparticles. MRI showed a marked decrease in signal intensity on T1- and T2-weighted images at the site of the labeled cells in vitro. These data suggest that novel positive-charged nanoparticles could be useful MRI contrast agents to monitor islet mass after transplantation.
authors.affiliation: Department of Advanced Medicine in Biotechnology and Robotics, Nagoya University Graduate School of Medicine , Nagoya , Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Oishi
authors.affiliation: Department of Advanced Medicine in Biotechnology and Robotics, Nagoya University Graduate School of Medicine, Nagoya, Japan; †Department of Gastroenterological Surgery, Transplant and Surgical Oncology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Noguchi
authors.affiliation: ‡ Nagoya Research Laboratory, MEITO Sangyo Co., Ltd. , Nagoya , Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Saito
authors.affiliation: Department of Advanced Medicine in Biotechnology and Robotics, Nagoya University Graduate School of Medicine , Nagoya , Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yukawa
authors.affiliation: Department of Advanced Medicine in Biotechnology and Robotics, Nagoya University Graduate School of Medicine , Nagoya , Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Miyamoto
authors.affiliation: § Department of Brain Functions, Division of Stress Adaptation and Protection, Research Institute of Environmental Medicine, Nagoya University , Nagoya , Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ono
authors.affiliation: ‡ Nagoya Research Laboratory, MEITO Sangyo Co., Ltd. , Nagoya , Japan.
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Murase
authors.affiliation: § Department of Brain Functions, Division of Stress Adaptation and Protection, Research Institute of Environmental Medicine, Nagoya University , Nagoya , Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Sawada
authors.affiliation: Department of Advanced Medicine in Biotechnology and Robotics, Nagoya University Graduate School of Medicine , Nagoya , Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Hayashi
keywords: Cationic nanoparticles; Dextran; In vivo imaging; Islet transplantation; Magnetic resonance imaging (MRI)