Copper-Selenocysteine Quantum Dots for NIR-II Photothermally Enhanced Chemodynamic Therapy

Chemodynamic therapy has been appealing for effective cancer treatment. Particularly, Fenton-like reactions catalyzed by Cu²⁺-based nanoparticles showed promising prospects. Herein, we fabricated copper-selenocysteine quantum dots (Cu-Sec QDs) with the majority of Cu⁺ by a facile and robust thermal titration process. No high temperature or pressure is needed for this synthetic route of QDs. The selenocysteine functioned as the reducing agent as well as the stabilizer, circumventing the poor water solubility and stability, leading to enhanced biocompatibility. The existence of Cu⁺ endowed the QDs the ability to catalyze the Fenton-like reaction without an extra reduction reaction of Cu²⁺ to Cu⁺. Moreover, the strong absorption in the near-infrared-II region (1000-1300 nm) of the final Cu-Sec QDs is in great favor of the chemodynamic therapy via the photothermally enhanced Fenton-like reaction. And the Cu-Sec QDs exhibited obvious cytotoxicity to various cancer cell lines. We believe that this facile and robust synthetic approach could open up another method for the fabrication of quantum dots toward the potential Fenton-like reaction-based applications in biological fields.