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Long-lasting moisture retention is a huge challenge to humectants, and effective methods or additives for promote these functions are limited, especially nano-additives. Carbon dots (CDs) have attracted increasing research interest due to its ultra-small size, excellent optical properties and low toxicity, etc. However, most of researches have been focused on the photoexcited CDs and its subsequent photophysical and chemical processes, such as photoluminescence, photodynamic, photothermal and photocatalytic behavior. The intrinsic chemo-physical properties of the pristine CDs are not fully explored. Here, we report an excellent moisture retention capability of a new carmine cochineal-derived CDs (Car-CDs) for the first time. The relationship between the structure of Car-CDs and its moisture retention capability is revealed. More interestingly, the effective applications of Car-CDs in moisturizing lipstick are demonstrated. This work expands the research and application of CDs into a broad, new area, potentially in skin care.

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 (1O2) 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.

Autophagy is indispensable in normal cellular processes, yet detrimental for cancer treatment because it severely lowers the therapy efficiency. One of the keys to solving this problem may lie in...

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