Targeted Nanoliposomes Loaded with IR780 Dye as a Multifunctional Nanoplatform for Photothermal and Photodynamic Cancer Therapy

Objective: During cancer treatment, the combined effect of photothermal therapy (PTT) and photodynamic therapy (PDT) has unique advantages over each of these methods alone. However, two lasers with different wavelengths are usually required to achieve the synergistic effect of PDT/PTT. In this study, we developed a multifunctional targeted nanoplatform for simultaneous combined photothermal and photodynamic therapy under 808 nm near-infrared laser irradiation. Methods: Small liposomes (~140 nm) specific to the tumor-associated antigen HER2 and loaded with near-infrared heptamethine cyanine dye IR780 were prepared. The targeting of liposomes to HER2 is mediated by the HER2-specific scaffold protein DARPin_9-29 located on the outer surface of liposomes. Tumor targeting of DARP-Lip(IR780) was evaluated in vitro using flow cytometry and confocal microscopy. The photothermal and photodynamic effects as well as cellular cytotoxicity of HER2-specific liposomes loaded with IR780 were evaluated in vitro under near-infrared light irradiation. Results and Discussion: It was established that IR780, when loaded in liposomes, retains photothermal and photodynamic properties: upon irradiation, the temperature of IR780-loaded liposome solution rapidly increases (up to 60°C within 60 s), and the production of reactive oxygen species is also detected. In vitro experiments demonstrated that HER2-specific liposomes containing IR780 exhibit photoinduced cytotoxicity against HER2-overexpressing cells, causing death of 50% of the cell population at a concentration of 2.85 μM. Conclusions: The results of this study suggest that HER2-specific liposomes containing IR780 have excellent targeted characteristics, and IR780 can be used as an active agent for simultaneous photothermal and photodynamic therapy.