Dual enzymes proteinosome with cascade activity for ultrasensitive glucose biosensing

Abstract

Catalytic cascades derived from the combination of multiple enzymes with efficient catalytic activity and high selectivity have attracted widespread attention in biosensing and biomedical applications. A key consideration in the development of cascade reaction systems is the combination of multiple enzymes to improve overall catalytic performance. Inspired by natural protein self-assembly, herein, proteinosomes formed by enzyme-surfactant complexes based on an interfacial assembly strategy are developed and they exhibit significant enhanced activity via cascade reaction of glucose oxidase (GOX) and horseradish peroxidase (HRP) that are located in proximity. The proteinosomes not only exhibit significantly elevated stability and reusability, but also possess enhanced cascade catalytic performance. These enhanced activities can be explained on the basis of the proximity effect of multiple enzymes within proteinosomes. Moreover, we employed highly efficient and reusability dual-enzyme-based proteinosomes to demonstrate the ultrasensitive detection of glucose, achieving a detection limit as low as 1.08 µM. Finally, the proteinosomes can be immobilized in a test strip for easy and fast glucose detection. Due to their ultra-sensitive detection limit, they can be used for non-invasive glucose detection. They can accurately assess glucose levels in saliva, yielding results highly congruent with those from commercially available assay kits. We further indicate the rapid capability of our system to detect glucose, as compared to commercial glucose kit. These finds demonstrate the potential of the test strip as a promising tool for daily glucose monitoring, and the facile approach presents an inventive solution for test strip development.