Light-Responsive Carbon Nitride Based Atomic Cu(I) Oxidase Mimics for Dual-Mode Total Antioxidant Capacity Assay

External light stimuli strategy under conventional conditions achieves a sustainable future due to its controllable spatial and temporal precision coupled with environmental friendliness. Herein, atomic Cu(I)-carbon nitride (Cu-CN) was synthesized and served as specific light-stimuli oxidase mimics for total antioxidant capacity (TAC) assay. Singlet oxygen (1O2) and hydroxyl radical (center dot OH) are the main intermediates, which can oxidize 3,3 ',5,5 '- tetramethylbenzidine (TMB) into its blue oxidant and therefore improve photothermal signal generation. Based on the intrinsic light responsiveness and photothermal conversion property, we established a colorimetric and photothermal dual-mode sensing platform. The proposed dual-mode assay presented a specific assay of ascorbic acid with LOD of 0.28 mu M and 0.15 mu M, respectively. This platform was further successfully applied to assess TAC of fruits and beverages. It is believed that the intelligently modulated activity and dual -mode detection function of such atomic enzyme mimics can offer a promising strategy for other analytical assays in high repeatability and reproducibility.