A novel copper-based nanosystem for augmented breast cancer photothermal and chemodynamic therapy

Among the most common cancers, metastasis and recurrence are the major causes of mortality in breast cancer. Current treatments, such as surgery and chemotherapy, have so far been inadequate in managing metastatic disease. This paper focuses on the potential of multi-functional copper-cysteine nanoparticles (Cu-Cys NPs) as a platform that incorporates PTT and CDT against this challenge. The dl- and l-Cu-Cys NPs were constructed through a straightforward coordination reaction between Cu²⁺ and cysteine ligands (dl and l), followed by detailed characterizations regarding their photothermal conversion efficiency and reactive oxygen species (ROS) generation capability. <i>In vitro</i> cytotoxicity and apoptosis of the 4T1 breast cancer cells treated with the prepared NPs were studied through MTT and apoptosis assays, respectively. Tumor growth, metastasis, and systemic toxicity <i>in vivo</i> were studied in intratumoral administrations in 4T1 tumor-bearing mice. The combined PTT and CDT not only remarkably ablated the primary tumor but also inhibited breast cancer metastasis with high efficiency. This work thus demonstrates the potential of combining PTT and CDT using a single nanosystem for treatment of metastatic tumors.