Ruthenium Cluster Incorporated Layered Double Hydroxide Nanozymes for the Colorimetric Detection of Total Antioxidant Capacity

The evaluation of the total antioxidant capacity (TAC) in the food detection area is essential for health monitoring. Herein, we have synthesized a layered double hydroxide, followed by the anchoring of a ruthenium cluster on the layered double hydroxide, represented by Ru@LDH. This Ru@LDH demonstrated synergistic catalase (CAT)-like and oxidase (OXD)-like activities, forming an efficient catalytic system for sensitive colorimetric TAC detection. Kinetic analysis revealed that Ru@LDH possesses superior OXD-like activity, achieving a maximum reaction rate ( V max ), which is higher than those of the most reported nanozymes in the food detection area. Under these circumstances, we have successfully established an efficient colorimetric detection proposal for the fast and sensitive recognition of both antioxidants, ascorbic acid (AA) and glutathione (GSH), reaching rather low detection limits of 0.013 and 0.0009 mM, respectively. This work not only provides a transportable tool for evaluating the nutritional value of foods based on TAC but also extends the application of nanozymes in the nutritional valuation of fruit.