Single-Atom Manganese Anchored on Carbon Dots for Promoting Mitochondrial Targeting and Photodynamic Effect in Cancer Treatment

The sustained rapid growth of tumor cells depends directly on the activity of mitochondria, which are important targets for many cancer drugs. Here, we report on a self-targeting method for mitochondria, a high atom efficiency nanoplatform, Mn/HA-CDs, made from hyaluronic acid-derived carbon dots (HA-CDs) and Mn2+ in a coordination structure of Mn-N5. We found that the Mn/HA-CDs with atomically dispersed Mn (0.73%) can generate reactive oxygen species (ROS) with a high atom economy. Particularly, its singlet oxygen (O-1(2)) quantum yield (0.40) is 3 times higher than that of the previous HA-CDs (0.13). Active absorption of Mn/HA-CDs by mitochondria inhibits mitochondrial superoxide dismutase (SOD) enzyme function, intensifies ROS damage to the mitochondria, and eventually promotes the photodynamic therapy (PDT) effect on tumor cells. Our findings suggest that targeting mitochondria with single-atom metal-anchored CDs for a better PDT effect is a viable method of treating tumors.