Bimetallic synergistic regulation of CuFe@TA nanozyme targeted boosting multi-enzymes activities for sensitive colorimetric detection of glucose

Nanozymes have been widely used in the field of biosensing owing to their high stability, low cost and adjustable catalytic activity. It is of great value to develop methods to construct nanozymes and to study their application. Here, a bimetallic synergistic enhancement CuFe@TA nanozyme was obtained by a simple and environmentally friendly one-pot aqueous phase method, in which Cu 2+ and Fe 3+ were bound to tannic acid (TA) by the strong coordination. In this process, the polyphenols in TA have reducing property that ensure the formation of hetero-valent metal pairs (Fe 3+ /Fe 2+ , Cu 2+ /Cu + ), thus enhancing the conversion of H 2 O 2 into more reactive radical species. Notably, the synthesized CuFe@TA nanozyme exhibited higher oxidase-like and peroxidase-like catalytic activities than a single metal ion due to the synergistic effect of the two transition metal components. Besides, based on the cascade catalysis of glucose oxidase (GOx) and CuFe@TA nanozyme, a sensitive colorimetric sensing platform for glucose assay was constructed with a good linear range of 3.03 ∼ 363.6  µM and a calculated limit of detection of 2.59  µM. This as-developed method was applied to detect glucose in real human serums and juice drink samples sensitively and accurately, consistent with measurement results made by commercial glucose meters. This work broadens the species of nanozymes, and provides a more sensitive glucose detection platform in medical diagnostics and the food industry.