Dual laser activatable brominated hemicyanine as a highly efficient and photostable multimodal phototherapy agent

Dual phototherapy agents have attracted great interest in recent years as they offer enhanced cytotoxicity on cancer cells due to the synergistic effect of photodynamic and photothermal therapies (PDT/PTT). In this study, we demonstrate a brominated hemicyanine (HC-1), which is previously shown as mitochondria targeting PDT agent, can also serve as an effective photosensitizer for PTT for the first time under a single (640 nm or 808 nm) and dual laser (640 nm + 808 nm) irradiation. Generation of reactive oxygen species and photothermal conversion as a function of irradiation wavelength and power were studied. Both single wavelength irradiations caused significant phototoxicity in colon and cervical cancer cells after 5 min of irradiation. However, co-irradiation provided near-complete elimination of cancer cells due to synergistic action. This work introduces an easily accessible small molecule-based synergistic phototherapy agent, which holds a great promise towards the realization of local, rapid and highly efficient treatment modalities against cancer.