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

Phototherapy,mainly induding 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 eficacy significantly,it has been attracting a lot of investigations in current days.Here,we introduce IR-52,a new mitochondria-targeting near infrared(NIR)fAuorescent small molecule,which possesses structure inherent PTT and PDT synergistic photother apeutic effects wit hout conjugation to specific ligands.After NIR light irradiation(808 nm,2 W/cm^(2),5min),both the hyperthermia and excessive singlet oaxygen levels were determined when dis-solving IR-52 in aqueous sohutions.In vitro photoinduced cytotoxicity studies showed signifcant 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 cytotoxicity.Further in vivo synergetic PDT and PTT effects were demonstrated by high tumor surface temperature and sigmificant inhibition of tumor growth.Our results strongly suggest that IR-52,which possesses excellent photosensitivity,may provide a promising strategy for tumor treatment with decreased side effects.