Hypotoxic and Rapidly Metabolic PEG-PCL-C3-ICG Nanoparticles for Fluorescence-Guided Photothermal/Photodynamic Therapy against OSCC

The development of agents for noninvasive photothermal/photodynamic therapies (PTT/PDT) against cancer remains challenging because most PTT agents cause side effects on normal tissues due to their high cytotoxicity and slow metabolism rate. We successfully synthesized an organic compound (C3), encapsulated in PEG-PCL with indocyanine green (ICG), to form hybrid nanoparticles (PEG-PCLC3-ICG NPs) for use as a new PPT/PDT agent to treat cancer with a single irradiation. Compared with conventional PPT agents, such as Au nanorods, C3 showed better photothermal conversion stability, lower cytotoxicity and a faster metabolic rate, ensuring promising PTT efficacy in eliminating tumors during in vivo application, while ICG was used as a PDT agent. With 808 nm laser irradiation at tumor sites, the PEG-PCL-C3-ICG NPs were able to simultaneously produce hyperthermia through C3 and produce reactive oxygen species as well as a fluorescence-guided effect through ICG to kill oral squamous cell carcinoma (OSCC) cells. The combination of these hypotoxic and metabolic hybrid nanoparticles with radiation therapy has potential for the future treatment of OSCC.