title: The use of microgel iron oxide nanoparticles in studies of magnetic resonance relaxation and endothelial progenitor cell labelling.
abstract: In vivo tracking of stem cells after transplantation is crucial for understanding cell-fate and therapeutic efficacy. By labelling stem cells with magnetic particles, they can be tracked by Magnetic Resonance Imaging (MRI). We previously demonstrated that microgel iron oxide nanoparticle (MGIO) provide superior tracking sensitivity over commercially available particles. Here, we describe the synthesis of MGIO and report on their morphology, hydrodynamic diameters (87-766 nm), iron oxide weight content (up to 82%) and magnetization characteristics (M(s)=52.9 Am(2)/kg, M(R)=0.061 Am(2)/kg and H(c)=0.672 A/m). Their MR relaxation characteristics are comparable to those of theoretical models and represent the first such correlation between model and real particles of varying diameters. A labelling study of primary endothelial progenitor cells also confirms that MGIO is an efficient label regardless of cell type. The facile synthesis of MGIO makes it a useful tool for the studying of relaxation induced by magnetic particles and cellular tracking by MRI.
authors.affiliation: Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. eddy.lee@uq.edu.au
authors.forename: Eddy S M
authors.initials: ES
authors.lastname: Lee
authors.forename: Borys
authors.initials: B
authors.lastname: Shuter
authors.forename: Jerry
authors.initials: J
authors.lastname: Chan
authors.forename: Mark S K
authors.initials: MS
authors.lastname: Chong
authors.forename: Jun
authors.initials: J
authors.lastname: Ding
authors.forename: Swee-Hin
authors.initials: SH
authors.lastname: Teoh
authors.forename: Olivier
authors.initials: O
authors.lastname: Beuf
authors.forename: André
authors.initials: A
authors.lastname: Briguet
authors.forename: Kam Chiu
authors.initials: KC
authors.lastname: Tam
authors.forename: Mahesh
authors.initials: M
authors.lastname: Choolani
authors.forename: Shih-Chang
authors.initials: SC
authors.lastname: Wang
mesh_terms: D004727:Endothelium / Q000166:cytology*; D005290:Ferric Compounds / Q000737:chemistry*; D005782:Gels; D008279:Magnetic Resonance Imaging; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D013234:Stem Cells / Q000166:cytology*
chemical_list: D005290:Ferric Compounds; D005782:Gels; C000499:ferric oxide