Cell membrane-targeted near-infrared carbon dots for imaging of hydrogen sulfide released through the cell membrane

Abstract As a novel endogenous gasotransmitter, hydrogen sulfide (H2S) is involved in many physiological and pathological processes closely related to intracellular and intercellular signal transduction. Herein, carbon dots with near-infrared fluorescence (NIR-CDs) were prepared by the facile hydrothermal method. The near-infrared fluorescence peak of the NIR-CDs reached 683 nm, and the fluorescence intensity remained stable after storing at room temperature within 70 days. The prepared NIR-CDs can be directly used for quantitative determination of H2S with LOD of 56 nM. More remarkably, the NIR-CDs could specifically locate on cell membrane and have been successfully used for imaging of endogenous H2S efflux from cell on the cell membrane. This work provides a new strategy for the design of cell membrane-targeted CDs as well as the further study of the mechanism of gaseous signal molecules in signal pathways and cellular communication. Furthermore, we found that the distribution of NIR-CDs and the commercial cell membrane dye (DiO) on cell membrane has some difference, which may due to the complementary relationship between the NIR-CDs and DiO in solubility. This finding makes it possible to design fluorescent probes for targeted imaging in different functional regions of the cell membrane in the future.