Fig. 8

Validation of intraoperative NIR-II image-guided cancer PTT with BPBBT NPs. a Schematic illustration of home-made system for NIR-II image-guided PTT of tumor in mice. b Photograph of NIR-II image-guided PTT of BALB/c mice bearing orthotopic CT26 colon cancer under anesthetic condition. c Measurement of laser spot adjusted to 1 mm or 3 mm in diameter for PTT. d Infrared (IR) thermal images before (0 min) and at the end of PTT of the tumor-bearing mice at 30 h following i.v. injection with BPBBT NPs (20 mg kg⁻¹) or PBS. In the BPBBT NPs-treated mice, primary and metastatic tumor was identified under NIR-II imaging followed by PTT with the indicated laser power density. In the PBS group, primary tumor was visualized by eye. Due to the invisible metastatic lesions, areas of cecum next to the primary lesion were randomly selected for PTT. e Temperature of the irradiated area-time curves from the IR thermal imaging of (d). f H&E staining of tumor or normal cecum of mice at 24 h following different treatment. In the BPBBT NPs-treated mice, primary and metastatic tumor was visualized under NIR-II imaging. In the PBS group, primary tumor was visualized by eye, while the metastatic lesions were invisible. Area of normal cecum was randomly selected. Tumor necrosis was characterized by extensive pyknosis (arrows), karyolysis (arrowheads), cytoplasmic acidophilia, and degradation of the extracellular matrix of tumor (asterisks)