Fig. 3

Photothermal performance and drug release behavior of drug-loaded LG. a Cell death percentages of 4T1 tumor cells at 0 h and 24 h after heating at various temperatures, i.e., 37 °C, 40 °C, 43 °C, and 45 °C. Data are shown as means ± SEM (n = 4 biologically independent samples). b PD-L1 expression on 4T1 tumor cells after different treatments. c Heating and cooling curves of IR820@LG for five cycles by turning on and off laser. d In vivo infrared thermal images of the tumor sites in 4T1-bearing mice irradiated immediately post intratumor injection with PBS, IR820 solution, and IR820@LG. Images were recorded at 0 min, 2 min, 5 min, and 10 min after irradiation. e Temperature variation curves of the tumor sites in 4T1-bearing mice after intratumor injection with PBS, IR820 solution, and IR820@LG, followed by NIR laser irradiation. Data are shown as means ± SEM (n = 3 biologically independent samples). f Cumulative release profiles of IgG from LG incubated with PBS with or without 808 nm laser illumination. Data are shown as means ± SEM (n = 3 independent samples). g Fluorescence IVIS images describing the intratumor retention time of IR820 solution, IR820@LG with or without the NIR laser irradiation in 4T1 tumor-bearing mice. h Fluorescence images of tumors stained by Cy3-labeled second antibody (for aPD-L1) and DAPI (for nuclei). Tumors were treated with free aPD-L1, aPD-L1@LG with light (aPD-L1@LG + L), and aPD-L1 without light (aPD-L1@LG-L) at different time points (scale bar: 200 μm)