Dual-Mode Paper Biosensing Platform Based on Oxidase-Like CoFeMn Nanozymes for Point-of-Care Detection of Glutathione

A paper-based biosensing platform is a point-of-care (POC) analysis toolkit for detection of various biomarkers. Nonetheless, its lack of high sensitivity, selectivity, and multi-signal readout poses a high degree of challenge. Herein, we introduce an interesting colorimetric-temperature dual-signal readout biosensor based on multifunctional CoFeMn biomimetic oxidase. Due to the cost-effectiveness, no additional detector requirement, dual-signal readout capacity, and darker signal change, CoFeMn hydroxide is innovatively fabricated by a facile hydrothermal method using Mn as an active center to construct a multifunctional signal tag for mimicking the structure of oxidase. This strategy allows CoFeMn hydroxide to exhibit an unusual oxidase-like activity, transforming O 2 into ·OH in the absence of H 2 O 2 and resulting in the generation of a colorimetric temperature dual signal by oxidizing 3,3′,5,5′-tetramethylbenzidine (TMB). We used glutathione (GSH) as the analyst and successfully applied this biosensor to determine GSH, which showed excellent analytical performance of rapidity, high specificity, sensitivity, and accuracy. Employing the colorimetric and temperature test strips, these toolkits are designed to visualize GSH. Benefiting from a relatively independent signal transduction pathway, the constructed test strip POC devices display satisfactory coupling efficiency and are further employed to monitor GSH in tumor cells. This research will be conducive to the rational design of a mimetic oxidase-based dual-response nanoprobe in paper-based POC devices, the exploration of more nanomaterial-derived mimetic oxidase, and the extension of their applications in medical diagnosis.