Identification of a mitochondria-targeting fluorescent small molecule for dual phototherapy

Phototherapy, mainly including photodynamic therapy (PDT) and photothermal therapy (PTT), is a noninvasive and effective approach for cancer treatment. Since integration of PDT and PTT for simultaneous synergistic PDT/PTT treatment enables us to improve phototherapeutic efficacy significantly, it has been attracting a lot of investigations in current days. Here, we introduce IR-52, a new mitochondria-targeting near infrared (NIR) fluorescent small molecule, which possesses structure-inherent PTT and PDT synergistic phototherapeutic effects without conjugation to specific ligands. After NIR light irradiation (808nm, 2W/cm2, 5min), both the hyperthermia and excessive singlet oxygen levels were determined when dissolving IR-52 in aqueous solutions. In vitro photoinduced cytotoxicity studies showed significant lower cell viabilities and higher necrotic/apoptotic rates when cancer cells were treated with IR-52 and irradiation, and its’ mitochondrial localization in cancer cells would partially explain its high...