Nanoplatforms with Remarkably Enhanced Absorption in the Second Biological Window for Effective Tumor Thermoradiotherapy

Thermoradiotherapy acts as an important antitumor modality because heating can increase the blood flow and improve the oxygen level in tumor, thus remission of hypoxia-associated resistance for radiotherapy (RT). However, most agents for thermoradiotherapy are used either in the first near-infrared biological window or low photothermal conversion efficiency. Here, a facile method to prepare CuxS/Au nanocomposites via reduction methods from CuxS templates in mild synthetic conditions (i.e., aqueous solution and room temperature) is presented. After the growth of Au nanoparticles, the CuxS/Au nanocomposites have greater benefits for photothermal efficiency than that of CuxS nanoparticles due to the enhanced absorbance in the second near-infrared window. Moreover, biocompatibility and stability of these nanocomposites are greatly improved by lipoic acid poly(ethylene glycol). After the tumors were irradiated with a 1064 nm laser, their oxygenation status is subsequently improved, and the combination of photothermal therapy and RT achieves remarkable synergistic therapeutic effects. This work provides a novel idea to design a new-generation nanomedicine for tumor thermoradiotherapy.