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).