Evaluating the therapeutic efficacy of radiolabeled BSA@CuS nanoparticle‐induced radio‐photothermal therapy against anaplastic thyroid cancer

Bovine serum albumin (BSA) has been employed as a mild biological template in nanoscale particles. Copper sulfide (CuS) has been used for photothermal therapy (PTT) in several studies. In this study, we aimed to synthesize the 131I‐labeled BSA‐modified CuS nanoparticles (131I‐BSA@CuS), with attributes of both radiotherapy and PTT, as a therapeutic agent against anaplastic thyroid carcinoma (ATC). BSA@CuS nanoparticles were prepared using the solvothermal reaction and then labeled with Na131I by the chloramine‐T method. The products were characterized and their cytotoxicity was investigated in vitro and in vivo. The therapeutic efficacy of 131I‐BSA@CuS was evaluated in ARO cell (an ATC cell line) subcutaneous tumors. The nanoparticles showed good biocompatibility and low toxicity in vitro and in vivo. BSA@CuS rapidly and effectively converted the light energy from an 808 nm laser into thermal energy with a conversion efficiency of 28.07%. SPECT/CT imaging demonstrated that the accumulation of radioactivity peaked within 24 hr and resided in the tumors for 5 days post intratumoral injection. In vivo assays indicated that, compared to monotherapy, the synthesized nanoparticles employing both PTT and radiotherapy possess better therapeutic efficacy against tumors. The synthesized nanomaterial showed uniform dispersion, good stability and aqueous solubility, excellent photothermal properties, and long‐term retention in ATC. Hence, combined radiotherapy and PTT can significantly inhibit tumor growth compared to monotherapy, and can be applied in clinical settings.