Bioinspired Single-Atom Sites Enable Efficient Oxygen Activation for Switching Anodic/Cathodic...

Area of Science:

• Electrochemistry
• Catalysis
• Biomedical Sensing

Background:

• Luminol-O2 electrochemiluminescence (ECL) is crucial for biosensing, but requires efficient co-reaction accelerators.
• Tuning accelerators for selective oxygen activation to control anodic/cathodic ECL remains a significant challenge.
• Reactive oxygen species (ROS) play a key role in modulating ECL reactions.

Purpose of the Study:

• To develop enzyme-inspired Fe-based single-atom catalysts (SACs) for controlled ROS generation and ECL switching.
• To investigate the structure-activity relationship of FeN5 and FeN4© SACs in ECL reactions.
• To construct a sensitive immunosensor for cancer biomarker detection based on enhanced ECL.

Main Methods:

• Synthesis and characterization of Fe-based SACs with FeN5 and FeN4© coordination structures.
• Electrochemical analysis of oxygen reduction activity and ROS generation.
• Investigation of ECL mechanisms for luminol-O2 systems using different SACs.
• Fabrication and performance evaluation of an immunosensor for cancer biomarker detection.

Main Results:

• FeN5 SACs selectively produce hydroxyl radicals, promoting efficient cathodic ECL.
• FeN4© SACs generate superoxide radicals, leading to inefficient anodic ECL.
• The N-induced electron redistribution in FeN5 sites facilitates O-O bond cleavage.
• A FeN5 SAC-based immunosensor achieved sensitive detection of cancer biomarkers.

Conclusions:

• Fe-based SACs with distinct coordination environments offer a strategy for tuning ROS generation and controlling ECL modes.
• FeN5 SACs are superior catalysts for cathodic ECL, enabling sensitive biosensing applications.
• This work provides insights into the rational design of single-atom catalysts for electrochemiluminescence applications.