A tumor-targeting fluorescent probe for ratiometric imaging of pH and improving PDT/PTT synergistic therapy

pH is an important indicator of various life activities and is closely associated with cancer. Thus, it is necessary to design an efficient method for detecting pH in tumors and seek a new strategy to enhance the efficiency of tumor therapy. In this paper, a novel tumor-targeting fluorescent probe, Cy-Bio-O, is designed and synthesized. The probe has a good ratiometric response to pH and successfully activates photodynamic and photothermal properties under acidic conditions. In cells experiments, Cy-Bio-O can image pH change by ratiometric signal and show excellent killing ability of cancer cells by PDT/PTT synergistic therapy. Moreover, the probe can image pH of tumor-bearing mice with high signal-to-noise ratio. With the help of tumor-targeting ability, Cy-Bio-O eventually achieve the ablation of solid tumors in tumor-bearing mice mediated by near-infrared (NIR) laser. As far as we known, this is the first exploration and design of a tumor-targeted fluorescent probe for tumor imaging and NIR PDT/PTT dual-modal synergistic therapy.