Silver nanoparticles@metal-organic framework as peroxidase mimics for colorimetric determination of hydrogen peroxide and blood glucose

As a major origin of energy for cellular activity and intermediates product of metabolism, glucose plays a significant role in biological activity. Thus, it is relatively vital to explore a sensitive and accurate approach to monitor blood glucose. Herein, a colorimetric biosensor for sensitive, rapid, and reliable monitoring of blood glucose was successfully established. In this sensing system, a nanocomposite of silver nanoparticles (AgNPs) depositing on the MIL-101 (Fe) surface ([email protected]) was employed as an excellent peroxidase mimic. Glucose could be effectively catalyzed by glucose oxidase (GOx) to produce hydrogen peroxide (H2O2) and gluconic acid. Afterward, the [email protected] nanozyme catalyzed the oxidation of the colorless material TMB into the blue product oxTMB by H2O2, causing a noticeable change in absorbance at 652 nm. A colorimetric glucose measurement platform was proposed with preferable simplicity and high sensitivity using GOx and [email protected] nanozyme with peroxidase-mimicking activity. The limit of detection of the established biosensor was down to 0.17 µM for H2O2 and 0.23 µM for glucose. More importantly, as a result of the application of this biosensor with human blood samples, glucose levels could be monitored with high accuracy, which indicated that this approach had great potential for diabetes therapy.