Light-Controlled Regulation of Dual-Enzyme Properties\nin YbGd-Carbon Quantum Dots Nano-Hybrid for Advanced Biosensing

Compared\nto nanozymes with single enzyme activity, those with multiple\nenzyme activities possess broader application potential due to their\ndiversified enzymatic functionalities. However, the multienzyme nanozymes\ncurrently face challenges of interference among different enzymatic\nactivities during practical applications. In this study, we report\nthe synthesis of a light-responsive YbGd-carbon quantum dots nano-hybrid,\ntermed YbGd-CDs, which exhibits controllable enzyme-mimicking activities.\nThis light-responsive behavior enables selective control of the enzymatic\nactivities. Under visible light irradiation, YbGd-CDs demonstrate\nrobust oxidase-like activity. Conversely, under dark conditions, they\nprimarily exhibit peroxidase-like activity. Leveraging the dual-enzyme-mimicking\ncapabilities of YbGd-CDs, we developed colorimetric assays for sensitive\ndetection of total antioxidant capacity (TAC) in both normal and cancer\ncells as well as d-amino acids in human saliva. This study\nnot only advances the synthesis of carbon-based nanozymes but also\nhighlights their potential in biosensing applications.