The development of near-infrared II fluorophore for tumor drug resistance reversal based on photothermal therapy

Multidrug resistance of tumor cells has greatly inhibited the therapeutic effect of chemotherapy. The development of reliable strategies to deal with tumor multidrug resistance is highly desirable for tumor therapy. In this work, novel near-infrared II (NIR II) fluorophores were rationally developed as photothermal reagents to reverse the drug resistance of tumor cells by reducing the related proteins expression, achieving high inhibition efficiency with the synergistic effect of chemotherapeutic drugs. By enhancing the electro-accepting effect, the emission peak of fluorophore shifted from 665 nm to 973 nm with acquiring NIR II materials, which presented outstanding photo-thermal conversion ability and improved thermal-stability compared to ICG. Then, by pre-treating with the photo-thermal treatment of NIR II fluorophore, the anti-tumor efficiency of chemotherapeutic drugs, including paclitaxel, cis-platinum and doxorubicin, was significantly enhanced towards drug-resistance tumor cells. The mechanism exploration revealed that drug resistance-related proteins would be remarkably reduced and enable the cells more sensitive towards drugs. Thus, this strategy demonstrated a promising and reliable approach to reverse the drug-resistance of tumor cells for efficient tumor inhibition in clinic.