Mechanism Exploration of Black Phosphorus Quantum Dots for Hydrogen Peroxide Modulation in Tumor Microenvironments

Nanozymes have emerged as promising candidates for cancer immunotherapy owing to their unique catalytic properties. In this study, we investigate black phosphorus quantum dots (BPQDs) as a representative nanozyme, unveiling their atomic-level mechanisms in regulating the tumor microenvironment (TME) through dual-functional catalytic activities that mimic peroxidase (POD) and catalase (CAT). Our findings demonstrate that BPQDs efficiently catalyze the conversion of hydrogen peroxide (H2O2) to oxygen (O2) within tumor cells, with activation energy barriers (Ea) of 0.35 and 0.65 eV for POD-like and CAT-like reactions, respectively, highlighting their exceptional energy conversion efficiency. This catalytic process not only alleviates tumor hypoxia but also enhances oxidative stress, leading to tumor cell apoptosis and significant inhibition of tumor growth. Moreover, by modulating the dynamic balance of reactive oxygen species (ROS), BPQDs transform the immunosuppressive, protumor TME into an immunostimulatory, antitumor TME, which may support oxidative stress regulation relevant to tumor treatment. This study offers atomistic-level mechanistic insights into the dual-functional catalytic behavior of BPQDs in modulating the tumor microenvironment, providing a potential strategy for enhancing the efficacy of cancer immunotherapy.