NIR-triggerable self-assembly multifunctional nanocarriers to enhance the tumor penetration and photothermal therapy efficiency for castration-resistant prostate cancer

Great challenges still remain in the management of patients with castration-resistant prostate cancer (CRPC) based on traditional treatments, and the rapid development of nanotechnology may find a breakthrough. Herein, a novel type of multifunctional self-assembly magnetic nanocarriers (IR780-MNCs) containing iron oxide nanoparticles (Fe3O4 NPs) and IR780 iodide was synthesized by an optimized process. With a hydrodynamic diameter of 122 nm, a surface charge of –28.5 mV and the drug loading efficiency of 89.6%, IR780-MNCs have increased cellular uptake efficiency, long-term stability, ideal photothermal conversion ability and excellent superparamagnetic behavior. The in vitro study indicated that IR780-MNCs have excellent biocompatibility and could induce significant cell apoptosis under the 808 nm laser irradiation. The in vivo study showed that IR780-MNCs highly accumulated at the tumor area could reduce the tumor volume of tumor-bearing mice by 88.5% under the 808 nm laser irradiation, but minimal damage to surrounding normal tissues. Since IR780-MNCs encapsulated a large number of 10 nm homogeneous spherical Fe3O4 NPs, which can be used as T2 contrast agent, the best window for photothermal therapy can be determined through MRI. In conclusion, IR780-MNCs have initially showed excellent antitumor effect and biosafety in the treatment of CRPC. This work provides novel insights into the precise treatment of CRPC by using a safe nanoplatform based on the multifunctional nanocarriers.