Scheme 1.

Schematic illustration for preparing NIR fluorescent Pdots and in vivo tracking of MSCs in a liver-resection mouse model. The NIR775 doped CN-PPV Pdots were prepared by using a reprecipitation method. The polymer matrix absorbs and transfers the excitation energy to the NIR dyes that emit strong NIR fluorescence. A cationic cell penetrating peptide R8 was used to modify the Pdot surfaces, yielding rapid and highly bright labeling of MSCs via cellular uptake. The Pdot-labeled MSCs were transplanted into the liver-resected model mice.