Synthesis of Liposomal Photosensitizers

For the synthesis of lipo-IRDye700DX, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) (Avanti), cholesterol (Avanti), DSPE-mPEG₂₀₀₀ (Avanti), and DSPE-PEG-IRDye700DX were mixed in chloroform at a molar ratio of 0.67, 0.30, 0.025, and 0.005, respectively. For the synthesis of lipo-BPD-PC, the lipids DPPC, cholesterol, DSPE-mPEG₂₀₀₀, and 20:0 lyso-PC-BPD were mixed in chloroform at a molar ratio of 0.665, 0.30, 0.03, and 0.005, respectively. Liposomes were prepared using a conventional thin-film hydration-extrusion method, by hydration in PBS and extrusion through 100 nm polycarbonate membranes (Whatman) [18 (link)–21 (link), 39 (link)].