FIGURE 3.

(A) Mean fluorescence intensity (MFI) of IR820 in tumors of mice at different times post-intravenous injection of IR820-PLGA NPs. The inset displays a representative image of IR820-PLGA NP fluorescence at 24 h after injection and the region of interest (ROI) in which the fluorescence intensity was measured. (B) Ex vivo analysis of IR820 signal in the brain, heart, liver, lungs, spleen, kidneys, and tumors of mice 24 h after they received intravenous injections of IR820-PLGA NPs or saline. (C) Mean tumor temperature in mice treated with saline, free IR820, or IR820-PLGA NPs during laser irradiation. These temperatures were recorded during the first of four treatment cycles. The red line at 42 °C indicates the threshold considered sufficient to induce PTT under the conditions in this study. (D) Tumor volume versus time in mice exposed to PTT mediated by IR820-PLGA NPs or various control treatments (n = 8 for all groups except saline + laser, for which n = 7). All treatments were injected intravenously at an IR820 concentration of 350 μM. Mice whose tumors received laser exposure were irradiated at 1.5 W/cm² for 5 min. Black arrows indicate the days of treatment injections (days 0, 7, 14, and 21) and red arrows indicate the days of laser irradiation (days 1, 8, 15, and 22). **p < 0.01.