Multivalent Sorbitol Probes for Near‐Infrared Photothermal Cancer Therapy

Abstract Photothermal therapy (PTT) is a targeted and non‐invasive therapeutic strategy for effective cancer treatment. Image‐guided PTT based on bifunctional near‐infrared (NIR) fluorophores has received significant attention recently and the development of NIR fluorophores is advised for targeted imaging and precise cancer therapy. In this study, a multivalent sorbitol‐conjugated NIR fluorophore (4Sorbitol‐800) is used as a photothermal therapeutic agent for in vivo cancer imaging and therapy because of the high tumor‐targetability of the sorbitol moieties and excellent photothermal properties of the NIR heptamethine cyanine core. This NIR fluorophore demonstrates an excellent photothermal effect, which increases the temperature of the tumor by 57.4 °C upon NIR laser irradiation (1.1 W cm⁻²) for 5 min. The volumes of HT‐29 tumors targeted by 4Sorbitol‐800 significantly decrease over 7 days after photothermal treatment. The 4Sorbitol‐800 developed in this study exhibits good in vivo safety and a highly efficient antitumor capability. Therefore, 4Sorbitol‐800 in combination with NIR laser irradiation has promising potential for future clinical applications with targeted photothermal cancer therapy.