Figure 2.

Efficacy of cell labeling.

Notes: In vitro MRI shows that GFP-MSCs labeled with SPION-loaded polymersomes have an obvious hypointense signal on T1WI, T2WI, and T2*WI, and decreased T2 value compared with unlabeled GFP-MSCs (A). Prussian blue staining shows abundant blue-stained particles inside GFP-MSCs labeled with SPION-loaded polymersomes (B), but no blue-stained particles in unlabeled GFP-MSCs (C) (Bar =100 µm). TEM shows numerous, dense, iron particles in the cytosol (arrows) of GFP-MSCs labeled with SPION-loaded polymersomes (D), whereas no such iron particles are found in unlabeled GFP-MSCs (E) (Bar =200 nm).

Abbreviations: MSC, mesenchymal stem cell; MRI, magnetic resonance imaging; SPION, superparamagnetic iron oxide nanoparticle.