Ascorbic acid-enhanced MOF-derived CeO2 for improved substrate selectivity in glucose detection

Rapid and precise blood glucose testing is vital for monitoring health and managing diabetes efficiently. Traditional glucose detection kits, reliant on natural enzymes, suffer from stability and cost issues. Nanozymes, with their flexibility, tunable activity, and stability, present a promising alternative. Yet, their catalytic activity and selectivity still lag behind natural enzymes. Integrating nanozymes with natural enzymes to form integrases offers a solution, maximizing the strengths of both for superior performance. In our study, we enhanced the Ce3+ content in MOF-derived CeO2 using a highly efficient reduction method with ascorbic acid (AA), resulting in a 6.1-fold increase in the maximum reaction rate of peroxidase-like activity towards H2O2 and improved substrate selectivity. This substrate selectivity effectively eliminates interference from oxidase-like activity in glucose detection. Through comparison with other reduction methods, we validated the benefits and mechanism of AA reduction in enhancing the peroxidase activity of CeO2. Subsequently, by employing AA-regulated CeO2 as a carrier for natural glucose oxidase, the integrase not only improved environmental tolerance but also enhanced catalytic activity, with detection linearity ranging from 50 to 1000 mu M. The collaborative detection method also demonstrated excellent detection capability for glucose in human serum samples, addressing the limitations of enzymatic detection methods.