Polydopamine-coated ferric oxide nanoparticles for R848 delivery for photothermal immunotherapy in breast cancer

Breast cancer, which requires comprehensive multifunctional treatment strategies, is a major threat to the health of women. To develop multifunctional treatment strategies, we combined photothermal therapy (PTT) with immunotherapy in multifunctional nanoparticles for enhancing the anti-tumor efficacy. Fe3O4 nanoparticles coated with the polydopamine shell modified with polyethylene glycol and cyclic arginine-glycyl-aspartic peptide/anisamide (tNP) for loading the immune adjuvant resiquimod (R848) (R848@tNP) were developed in this research. R848@tNP had a round-like morphology with a mean diameter of 174.7 ± 3.8 nm, the zeta potential of −20.9 ± 0.9 mV, the drug loading rate of 9.2 ± 1.1 %, the encapsulation efficiency of 81.7 ± 3.2 %, high photothermal conversion efficiency and excellent magnetic properties in vitro. Furthermore, this research also explored the anticancer efficacy of nanoparticles against the breast cancer under the near-infrared (NIR) light (808 nm) in vitro and in vivo. R848@tNP-based NIR therapy effectively inhibited the proliferation of breast cancer cells. Moreover, R848@tNP mediated PTT significantly enhanced the maturation of dendritic cells in vitro. Additionally, R848@tNP enhances the anti-tumor effect and evoked an immune response under NIR in vivo. Furthermore, the biosafety of R848@tNP was fully investigated in this study. Collectively, these results clearly demonstrate that R848@tNP, with magnetic resonance imaging characteristics, is a potential therapeutic for breast cancer that combines PTT with the immunotherapy.