▎ 摘 要
The design of a nonenzyme sensor for lactose imaging in living cells is still a challenge nowadays. Enlightened by the saccharide-saccharide recognition at the cell surface, we prepared a graphene quantum dots-glucosaminic acid (GQDs-GA)-based fluorescent sensor for detection of lactose in living cells with high selectivity and sensitivity. GA acts as a receptor for lactose, while GQDs acts as a fluorescence signal transducer. Upon lactose addition, the fluorescence peaks at 315 and 429 nm were significantly enhanced owing to the blocking of photoinduced electron transfer. The interaction of the GQDs-GA sensor with lactose was mainly governed by the amide center dot center dot center dot OH and OH center dot center dot center dot n hydrogen bonding, supported by 1H NMR and density functional theory (DFT) cal-culations. A good linear relationship with the concentration of lactose was obtained over the range of 9.9 -142.9 mu M with a detection limit of 0.35 mu M. The proposed sensor was used to detect lactose in real samples (tap water, milk, and honey) with a recovery range of 100.16-103.32%. More importantly, the GQDs-GA sensor can be used to track lactose in living cells. This work provides new insights into development of nonenzyme-based biosensor for single saccharide.