Effect of different magnetic nanoparticle coatings on the efficiency of stem cell labeling

Maghemite nanoparticles with various coatings were prepared by the coprecipitation method and characterized by transmission electron microscopy, dynamic light scattering and IR in terms of morphology, size, polydispersity and surface coating. The labeling efficiency and the viability of both rat and human mesenchymal stem cells labeled with Endorem®, poly(l-lysine) (PLL)-modified Endorem®, uncoated γ-Fe2O3, d-mannose-, PLL- or poly(N,N-dimethylacrylamide) (PDMAAm)-coated γ-Fe2O3 nanoparticles were compared. Coated γ-Fe2O3 nanoparticles labeled cells better than did Endorem®. High relaxation rates and in vitro magnetic resonance imaging of cells labeled with coated nanoparticles showed clearly visible contrast compared with unlabeled cells or cells labeled with Endorem®.