High-efficient synthesis of carbon quantum dots from orange pericarp as fluorescence turn-on probes for Ca 2+ and Zn 2+ ion detection and their application in trypsin activity characterization.

The obtained NCQDs contain high photo-stability, excellent PL activity, and efficient fluorescent emission based on excitation. The results of kinetic studies revealed the ability of NCQDs to inhibit trypsin activity in a non-competitive model, which qualifies them as potent inhibitors and quenchers of trypsin. It can be suggested that the synthesized NCQDs have the potential of functioning as a sustainable and eco-friendly source for various applications such as sensors for detecting Ca and Zn and trypsin biosensor for determining enzyme activity.