Flexible multi-enzyme biosensor based on MOF-74/Argdot biomimetic mineralization for dynamic multi-analyte monitoring in sweat

Although natural enzymes exhibit high selectivity and catalytic efficiency, their complex structures and inherent variability limit the long-term monitoring capabilities. Metal-organic frameworks (MOFs) biomimetic mineralization offers stability protection for enzymes, but it increases diffusion obstruction and reduces activity of encapsulated enzymes. To overcome these challenges, a biosensor based on MOF-74 biomimetic mineralization of three enzymes and combined with arginine-derived carbon dots (Argdot) was designed for monitoring key indicators (glucose, lactic acid, and xanthine) of muscle fatigue. The Boron‑nitrogen co-doped porous carbon nanospheres/reduced graphene oxide electrode (B,NMCNS/rGO) was used as the sensing substrate and the MOF-74/enzyme/Argdot was served as selective recognition layer. The detection sensitivities for glucose, lactic acid, and xanthine are 182.4 nA μM −1  cm −2 , 386.6 nA mM −1  cm −2 , and 207.6 nA μM −1  cm −2 . The sensors exhibit excellent linear ranges that fully encompass the physiological concentration intervals of all three biomarkers in sweat, and maintain over 94 % of its current response over 60 day-storage. Experiments conducted under several conditions demonstrate that the sensing system can dynamically monitor the variation of glucose, lactic acid, and xanthine in sweat. This study highlights the considerable promise of a noninvasive and continuous sensing system for point-of-care assessment and effective management in sports health.