Design of iron oxide nanoparticles with different sizes and surface charges for simple and efficient labeling of mesenchymal stem cells.

The objective of this study is to prepare iron oxide nanoparticles with different sizes and surface potentials and evaluate the labeling efficiency of bone marrow-derived mesenchymal stem cells (MSC). The ferric and ferrous ions were co-precipitated in the presence of pullulan or the cationized and anionized derivatives to prepare iron oxide-pullulan nanoparticles of a contrast agent of magnetic resonance imaging (MRI). The size and surface potential of iron oxide-pullulan nanoparticles were changed by altering the mixing molar ratio of pullulan OH groups to ferric ions and the mixing percentage of pullulan derivatives, respectively. When MSC were labeled with the iron oxide-pullulan nanoparticles by the co-culture for 1h, the labeling efficiency and (1)H MRI relaxivity were greatly influenced by the particle size and surface potential, while the labeling procedure did not affect the viability and differentiation ability of MSC. These findings indicate that iron oxide-pullulan nanoparticle is a promising tool for the MRI labeling of MSC. (c) 2009 Elsevier B.V. All rights reserved.