The size distribution of Lipo/pB-DOX/ICG, Lipo/pB-DOX, and Lipo/ICG was measured using a Malvern Zetasizer Nano Series instrument (Nano ZS, Malvern Instruments, UK), and their morphology was observed by transmission electron microscopy (TEM, Titan G2-F20, FEI, USA). The aforementioned formulations were monitored by UV-vis-NIR spectroscopy (260-Bio, Thermo Fisher Scientific). After ultrafiltration centrifugation and organic solvent extraction, the encapsulation efficiencies (EE) and loading contents (LC) of pB-DOX and ICG in the liposomes were quantified and calculated using HPLC and UV-vis-NIR spectroscopy, respectively. UV-vis-NIR absorption at 784 nm was used to determine the ICG concentration.
To study the release behavior of pB-DOX and ICG in the liposomes, nanosuspension for each group (1 mL, containing 235 µg of pB-DOX and/or 150 µg of ICG) was sealed in a dialysis bag (MWCO: 3.5 kDa ) and dialyzed in 30 mL PBS with acidic pH (5.5) or 0.2 % Tween 80. At certain intervals, a 100 µL aliquot of the solution outside the bag was withdrawn for HPLC and UV-vis-NIR analyses.
To study the release behavior of pB-DOX and ICG in the liposomes, nanosuspension for each group (1 mL, containing 235 µg of pB-DOX and/or 150 µg of ICG) was sealed in a dialysis bag (MWCO: 3.5 kDa ) and dialyzed in 30 mL PBS with acidic pH (5.5) or 0.2 % Tween 80. At certain intervals, a 100 µL aliquot of the solution outside the bag was withdrawn for HPLC and UV-vis-NIR analyses.