Green synthesis of carrier-free curcumin nanodrugs for light-activated breast cancer photodynamic therapy

Photodynamic therapy (PDT) is a promising procedure for breast cancer therapy. Curcumin (Cur), a hydrophobic polyphenol derived from the spice turmeric, has been considered as a potential photosensitizer for PDT with evoked immune response, excellent safety, and low cost. However, the translation of curcumin in clinical cancer therapy suffers from an insufficient therapeutic dose in tumor tissues due to its poor solubility and low bioavailability. In this study, carrier-free curcumin nanodrugs (Cur NDs) were prepared without using any toxic solvents through a facile and green reprecipitation method. Cur NDs exhibited distinct optical properties, light-sensitive drug release behavior, resulting in increased reactive oxygen species (ROS) generation and PDT efficacy on breast cancer cells compared with free Cur. Furthermore, cell apoptosis during Cur-based PDT was concomitant with the activation of the ROS-mediated JNK/caspase-3 signaling pathway. Overall, our carrier-free Cur nanodrugs may be promising candidates for facilitating the efficacy and safety of PDT against breast cancer.