title: Low molecular weight alkyl-polycation wrapped magnetite nanoparticle clusters as MRI probes for stem cell labeling and in vivo imaging.
abstract: Superparamagnetic iron oxide (SPIO) nanoparticles are potential probes for noninvasive cell tracking, but the design of safe probes coupled with high labeling efficiency is still an important objective for such application. In this study, an efficient SPIO probe has been developed for mesenchymal stem cells (MSCs) labeling and tracking. Different from many other systems involving high molecular polycations, we chose low molecular weight amphiphilic PEI2k to form stable nanocomplexes with SPIO nanoparticles. The probe can hold multiple SPIO nanoparticles with a controlled clustering structure, leading to much higher T(2) relaxivities compared to single SPIO nanoparticles. Labeled MSCs are unaffected in their viability, proliferation, or differentiation capacity. The iron uptake process in MSCs displays a time- and dose-dependent behavior. Transmission electron microscopy reveals that the nanoprobes are internalized into the cytoplasm of MSCs. Subcutaneous injection of the labeled MSCs dispersed in a collagen type I hydrogel showed strong image contrast against unlabeled cells under a clinical 3T magnetic resonance imaging (MRI) scanner up to 19 days post-transplantation. This study provides an important alternative to label MSCs at optimized low dosages with high efficiency, and the probe may be useful to label other biologically important cells for imaging studies.
authors.affiliation: National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Liu
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Wang
authors.forename: Jian
authors.initials: J
authors.lastname: Lu
authors.forename: Chunchao
authors.initials: C
authors.lastname: Xia
authors.forename: Fabao
authors.initials: F
authors.lastname: Gao
authors.forename: Qiyong
authors.initials: Q
authors.lastname: Gong
authors.forename: Bin
authors.initials: B
authors.lastname: Song
authors.forename: Xuna
authors.initials: X
authors.lastname: Zhao
authors.forename: Xintao
authors.initials: X
authors.lastname: Shuai
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Chen
authors.forename: Hua
authors.initials: H
authors.lastname: Ai
authors.forename: Zhongwei
authors.initials: Z
authors.lastname: Gu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D058948:Cell Tracking / Q000379:methods*; D002478:Cells, Cultured; D005293:Ferritins / Q000235:genetics; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D051379:Mice; D008807:Mice, Inbred BALB C; D046529:Microscopy, Electron, Transmission; D008970:Molecular Weight; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D011990:Receptors, Transferrin / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D011990:Receptors, Transferrin; D005293:Ferritins; D052203:Ferrosoferric Oxide