Near-Infrared IIb Emitting Nanoprobe for High-Resolution Real-Time Imaging-Guided Photothermal Therapy Triggering Enhanced Anti-tumor Immunity.

The change of tumor vessels is an important indicator for the evolution of cancer, which largely reflects the curative degrees. Therefore, in situ monitoring of the change of tumor vessels during the course of medical treatment becomes an urgent need for the implementation of therapy. Photothermal therapy (PTT), a promising treatment for cancer, has attracted extensive attention. So far, it lacks precise methods for visualizing tumor vessels during the PTT treatment in a noninvasive way. Herein, the quantum-dot-based nanoprobes emitting in the 1500-1700 nm range of the second near-infrared region (NIR-IIb window) with good photothermal conversion performance are conjugated with arginine-glycine-aspartate peptide and successfully applied to imaging-guided photothermal therapy. Owing to the high resolution of NIR-IIb fluorescence imaging, the process of significant reduction of tumor-associated vessels and abnormal angiogenesis is clearly demonstrated. Encouragingly, the immune response can be activated after the photothermal therapy. Excellent therapeutic efficacy with suppressed recurrence is achieved under the synergistic effect of destroying tumor tissues and enhancing immunity. This work provides a noninvasive method to evaluate the changes of tumor microvessel density for anti-angiogenesis therapy and affords a powerful tool for in vivo research of preclinical animal models and precise cancer therapies.