High-performance enzymatic biofuel cell enabled by a tolerance-enhanced MOF/cascade-enzyme anode catalyst

Enzymatic biofuel cells (EBFCs) are green energy-conversion devices widely used in biosensing applications. However, unprotected enzyme is easily destabilised and may eventually deactivate under practical application scenarios. Thus, the activity of biological enzymes is constrained by their inherent fragility. Furthermore, in single-enzyme systems, the accumulation of intermediate products often inhibits enzymatic activity. Herein, we innovatively developed carbon dots (CDs) and cascade enzyme-glucose oxidase (GOx)/horseradish peroxidase (HRP) co-embedded hydrophilic MAF-7 biocatalyst (MAF-7@GOx-HRP/CDs). The MAF-7@GOx-HRP/CDs exhibit high electrocatalytic stability even under elevated temperatures and in the presence of molecular inhibitors. In real samples, devices employing the MAF-7@GOx-HRP/CDs bioanode achieved a 10-fold increase in power density (41.98 μW cm −2 vs 3.93 μW cm −2 ) compared with those using unprotected GOx-HRP/CDs. In addition, the developed biosensors demonstrated a linear detection range of 0.05–30 μM with a low detection limit of 0.04 μM. The sensor accuracy reached 98.4% when validated against the high-performance liquid chromatography (HPLC) method. This study demonstrates that integrating enzyme cascade systems into MOFs enhances biocatalytic activity, providing new insights for the development of advanced enzymatic catalysts for biosensing applications. Using an in situ growth method, the GOx-HRP cascade system and CDs were co-encapsulated in an organic metal framework (MAF-7) to synthesize a novel composite biocatalyst, MAF-7@GOx-HRP/CDs. The protective effect of MAF-7 enables the enzyme to maintain higher catalytic activity under adverse conditions. CDs enhance the catalyst's conductivity while effectively increasing the enzyme loading capacity. The EBFC using this catalyst as the anode catalyst achieves accurate detection of glucose in real samples. • An innovative MAF-7 biocatalyst co-embedded with CDs and GOx/HRP was developed. • MAF-7@GOx-HRP/CDs exhibits excellent resistance to biocorrosion and interference. • EBFCs exhibited 10-fold enhanced power density and 1.5-fold stability enhancement. • The biosensors displayed exceptional accuracy, selectivity and sensitivity.