Figure 2: (a) The time-lapse optical images showed that liposome containing 10 mM CF, with the size of 200–240 nm, fast accumulated in rat liver as soon as 5 min after i.v. administration. The fluorescence intensity observed from liver gradually increased and reached its plateau in 100 min. To evaluate the stability of these on-site DPPG-liposomes in liver, the microdialysis probe with the molecular size cutoff at 100 kDa was implanted in situ to simultaneously analyze the fluorescence signals of extracellular fluid in liver, as indicated with a red-dotted circle. (b) The profile of fluorescence intensity in microdialysate showed no significant variation throughout the concurrent optical imaging course after the i.v. injection of CF-encapsulating liposomes.