Chitosan-coated poly(lactic-co-glycolic acid) perfluorooctyl bromide nanoparticles for cell labeling in (19)F magnetic resonance imaging.

Noninvasive therapeutic cell tracking methods in living animals are important for understanding cell function and fate in connection with cell therapy. Here we report a new particle system based on chitosan-coated poly(lactic-co-glycolic acid) perfluorooctyl bromide (PLGA PFOB) nanoparticles designed for (19)F magnetic resonance imaging (MRI) cell tracking. Chitosan was adsorbed onto the PLGA PFOB nanoparticles through electric interactions, which led to an increase in the hydrodynamic size and a surface charge proportional to the coating weight ratio. Confocal laser scanning microscopy, flow cytometry analysis and (19)F-MRI showed that to achieve the highest labeling efficiency in vitro, the optimal weight ratio of chitosan to the PLGA PFOB nanoparticles was 1:10 for human mesenchymal stem cells (hMSCs) and 1:100 for Raw 264.7 macrophages. In vivo(19)F-MRI showed that (19)F labeled hMSCs remained at the injected site 24h after injection. Thus, this study validates that chitosan-coated PLGA PFOB nanoparticles have the potential to track cell migration in vivo.