Unraveling the stress-induced toxicity of black phosphorus nanosheets and the underlying mechanism

The unique physicochemical properties of black phosphorus (BP) nanomaterials make them extremely versatile, and growing concern has emerged regarding their biocompatibility. Here, we investigate the toxic profile of BP nanosheets under oxidative stress conditions in living cells and a simple animal model, Caenorhabditis elegans. Under normal conditions, BP nanosheets exhibit no adverse effects on cells and worms. However, the ability of cells and worms to resist oxidative stress is significantly impaired by BP nanosheets. Mechanism studies show that hydroxyl radical overproduction is induced by the reaction between BP nanosheets and H₂O₂, which may disrupt mitochondrial integrity and promote the leakage of cytochrome c from mitochondria into cytoplasm. Meanwhile, BP nanosheets are degraded under oxidative stress conditions, providing opportunities for BP nanosheets to interact with cytochrome c, thereby disrupting the cellular antioxidant defense system and ultimately producing toxicity. Our research uncovers the potential mechanism of BP nanosheets with oxidative stress-induced toxicity.