SDF-1-loaded PLGA nanoparticles for the targeted photoacoustic imaging and photothermal therapy of metastatic lymph nodes in tongue squamous cell carcinoma

The combination of photothermal therapy and targeted chemotherapy can produce much greater cytotoxicity than chemotherapy. Herein, we developed multifunctional targeted polymeric nanoparticles (NPs) loaded with indocyanine green (ICG) and doxorubicin (DOX) for the targeted photoacoustic imaging and photothermal ablation of oral cancer cells. The chemokine SDF-1, a specific antibody, was conjugated to NPs by the carbodiimide method. The NPs were automatically targeted to tumour tissue in vitro and in vivo through CXCR4-SDF-1 interactions. The results of in vivo and in vitro photoacoustic imaging and photothermal therapy experiments showed that the multifunctional NPs had excellent photoacoustic imaging characteristics and photothermal therapy capabilities. The photothermal material heated rapidly after laser irradiation, and the resulting heat increased cell metabolism and membrane permeability, which increased cellular NP uptake. The encapsulated drug (DOX) was released immediately after the liquid core was transformed into a gas via laser effects, which killed tumour cells while producing strong photoacoustic signals in vitro and in vivo. Thus, we concluded that the chemokine SDF-1 can be applied for the targeted chemotherapy of metastatic lymph nodes of oral squamous cell carcinoma (OSCC) and is more effective for treating oral cancer when combined with photothermal therapy than when used alone.