Peroxynitrite activatable NIR-II probe for tumor diagnosis and photothermal therapy in vivo.

Peroxynitrite (ONOO) is a bioactive molecule involved in various biochemical processes, and the abnormal concentration fluctuations of ONOO in living systems are closely associated with various diseases, including cancer. An important characteristic of the tumor microenvironment is the overexpression of ONOO, highlighting the significance of specific detection of ONOO in distinguishing between tumor tissue and normal tissue. A single near-infrared second window (NIR-II) molecular probe integrated fluorescence imaging and photothermal therapy can achieve precise localization and effective ablation of deep-seated tumor tissue. However, it still remains challenges. (87) RESULTS: In this study, we present a probe (BDⅡ-ONOO) that integrates NIR-II fluorescence imaging and photothermal therapy for the specific detection of ONOO. The probe exhibits excellent selectivity, high sensitivity, low toxicity and high biocompatibility. In the presence of ONOO, the probe can quickly respond to ONOO and emit NIR-II fluorescence at 900 nm with 7.6-fold change in fluorescence intensity. In addition, the probe BDⅡ-ONOO exhibits a high photothermal conversion efficiency of 41.6 % under 808 nm laser irradiation in the presence of ONOO. In vivo imaging results indicate that the probe BDⅡ-ONOO not only effectively distinguishes tumor tissue from normal tissue but also performs photothermal treatment on 4T1 tumor without apparent biological toxicity. (112) SIGNIFICANCE: This work provides insights for the future development of tumor-specific diagnostic and therapeutic approaches with good biocompatibility and deep tissue penetration. The probe described in this work may be employed as a powerful tool for the diagnosis and precise treatment of tumors in vivo. (44).