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) analysistoolkit for detection of various biomarkers. Nonetheless, its lackof high sensitivity, selectivity, and multi-signal readout poses ahigh degree of challenge. Herein, we introduce an interesting colorimetric-temperaturedual-signal readout biosensor based on multifunctional CoFeMn biomimeticoxidase. Due to the cost-effectiveness, no additional detector requirement,dual-signal readout capacity, and darker signal change, CoFeMn hydroxideis innovatively fabricated by a facile hydrothermal method using Mnas an active center to construct a multifunctional signal tag formimicking the structure of oxidase. This strategy allows CoFeMn hydroxideto exhibit an unusual oxidase-like activity, transforming O-2 into center dot OH in the absence of H2O2 and resultingin the generation of a colorimetric temperature dual signal by oxidizing3,3 ',5,5 '-tetramethylbenzidine (TMB). We used glutathione(GSH) as the analyst and successfully applied this biosensor to determineGSH, which showed excellent analytical performance of rapidity, highspecificity, sensitivity, and accuracy. Employing the colorimetricand temperature test strips, these toolkits are designed to visualizeGSH. Benefiting from a relatively independent signal transductionpathway, the constructed test strip POC devices display satisfactorycoupling efficiency and are further employed to monitor GSH in tumorcells. This research will be conducive to the rational design of amimetic oxidase-based dual-response nanoprobe in paper-based POC devices,the exploration of more nanomaterial-derived mimetic oxidase, andthe extension of their applications in medical diagnosis.