Highly Fluorescent Chiral N‐S‐Doped Carbon Dots from Cysteine: Affecting Cellular Energy Metabolism

Abstract Cysteine‐based chiral optically active carbon dots (CDs) and their effects on cellular energy metabolism, which is vital for essential cellular functions, have been barely reported. A green and effective synthesis strategy for chiral N‐S‐doped CDs (fluorescence quantum yield ca. 41.26 %) based on hydrothermal treatment of l ‐ or d ‐cysteine at as low as 60 °C has been developed. This suggested that cysteine was instable in aqueous solutions and acts as a warning for high‐temperature synthesis of nanomaterials using cysteine as stabilizer. Human bladder cancer T24 cells treated with l ‐CDs showed up‐regulated glycolysis, while d ‐CDs had no similar effects. In contrast, no disturbance to the basal mitochondrial aerobic respiration of T24 cells was caused by either chiral CD.