Multi-nanozyme cascade system for boosting colorimetric sensing by selective etching bimetallic MOFs.

Area of Science:

• Materials Science
• Catalysis
• Analytical Chemistry

Background:

• Rational engineering of multienzyme systems is crucial for high-performance cascade catalysis in sensing.
• The initiation step significantly impacts catalytic efficiency.
• CoFe Prussian blue analogue (CoFePBA) serves as an ideal template for multi-enzyme design due to its dual-metal ion properties.

Purpose of the Study:

• To develop a defect-engineered CoFePBA material for enhanced multi-enzyme cascade catalysis.
• To create a sensitive colorimetric sensor for glutathione (GSH) detection.

Main Methods:

• Selective induction of cobalt defects in CoFePBA using deep eutectic solvents (DES) under mild conditions.
• Construction of a three-enzyme cascade system (oxidase, superoxide dismutase, peroxidase).
• Utilizing the inhibitory effect of GSH on the cascade activity for sensor development.

Main Results:

• DES treatment enhanced active sites and the Co²⁺/Co³⁺ ratio in CoFePBA, boosting cascade initiation.
• The three-enzyme cascade achieved a two-fold increase in H₂O₂ yield.
• A rapid colorimetric sensor for GSH was developed with a detection range of 0.5-160 μM and a limit of detection of 0.15 μM.

Conclusions:

• DES-based defect engineering offers a selective, low-toxicity, and structure-preserving method for MOF modification.
• Activated initial cascade steps via defect engineering significantly enhance catalytic activity.
• This approach provides a viable route for preparing high-performance dual-metal catalysts for cascade reactions and sensing.