Phototheranostic nanoplatform based on a single cyanine dye for image-guided combinatorial phototherapy

This study represents a novel phototheranostic nanoplatform based on the near-infrared (NIR) heptamethine cyanine dye, IR775, which is capable of concurrent real-time fluorescence imaging and cancer eradication with combinatorial phototherapy. To achieve water solubility and enhance tumor delivery, the hydrophobic IR775 dye was loaded into a biocompatible polymeric nanoparticle with a diameter of ~40nm and slightly negative surface charge (-2.34mV). The nanoparticle-encapsulated hydrophobic IR775 dye (IR775-NP) is characterized by an enhanced fluorescence quantum yield (16%) when compared to the water soluble analogs such as ICG (2.7%) and IR783 (8%). Furthermore, the developed IR-775-NP efficiently generates both heat and reactive oxygen species under NIR light irradiation, eradicating cancer cells in vitro. Finally, animal studies revealed that the IR775-NP accumulates in cancer tumors after systemic administration, efficiently delineates them with NIR fluorescence signal and completely eradicates chemo resistant cancer tissue after a single dose of combinatorial phototherapy.