Photoimmunotherapy has attracted much attention recently for the treatment of metastatic
tumors. The development of smart nanocomposites for imaging-guided
therapies is needed to improve the efficacy of
cancer treatment. Herein, a PEGylated nanocomposite was developed for photothermal-
immunotherapy. In particular, this nanocomposite was formulated by hybridizing Fe3O4 nanoparticles (FNPs) with reduced-
graphene oxide (rGO) through electrostatic interaction, modified by PEG-NH2 on the surface of FNPs/rGO. The FNPs/rGO-PEG nanocomposites are excellent agents for
photothermal therapy (PTT) under irradiation by an 805 nm
laser. This nanocomposite could promote the activity of the host antitumor immune response efficiently because of the reduction of tumor-associated macrophages by the incorporation of FNPs. In our experiments, we observed FNPs/rGO-PEG based PTT induced immunogenic cell death accompanied by the release of danger-associated molecular patterns. We also found that FNPs/rGO-PEG +
laser irradiation of animal
tumors could activate dendritic cells (DCs) in
tumor draining lymph nodes. In vivo antitumor studies revealed that FNPs/rGO-PEG nanocomposites, when combined with
laser irradiation, could result in desirable photothermal effects and destroy primary
tumors. Moreover, intratumoral injection of FNPs/rGO-PEG nanocomposites into 4T1 orthotopic mouse
breast tumors, in combination with near-infrared
laser irradiation, significantly increased the median survival time of
tumor-bearing animals. FNPs/rGO-PEG nanocomposites could also be used for magnetic resonance imaging, which may lead to a MRI-guided photothermal-
immunotherapy for metastatic
cancers. This study could lead to a
cancer treatment strategy that combines PTT with
immunotherapies using FNPs/rGO-PEG nanocomposites.