Combination of magnetic nanoparticles and transfection agents: Physicochemical properties for cell labeling

Abstract There is increasing interest in using superparamagnetic iron oxide (SPIO) nanoparticles to label various cells for monitoring their temporal and spatial migration in vivo by magnetic resonance imaging (MRI). To enhance the labeling efficiency of SPIO nanoparticles, complexing of polycationic transfection agents (TAs) to SPIO is often introduced through electrostatic interactions. In this study, we investigate the changes in physicochemical properties such as particle size, zeta potential by combining TAs and clinically approved SPIO nanoparticles. Also, we investigate the possible relationship of the change in physicochemical properties with the changes in T2 relaxation properties of TA–SPIO complex. Our results show that among various TA–SPIO complexes, the Feridex–PLL complexes seem to be most suitable for magnetic labeling of the cell with the formation of stable suspension and high R2 values.