A Target Responsive Metal Organic Framework Derived Bimetallic Apta-Switch for Reagentless Molecular Recognition.

Area of Science:

• Materials Science
• Electrochemistry
• Biosensing

Background:

• Metal-organic frameworks (MOFs) offer tunable properties for advanced material design.
• Functional DNA (fDNA) provides high specificity for molecular recognition.
• Electrochemical biosensors require robust immobilization matrices and signal transduction mechanisms.

Purpose of the Study:

• To design and fabricate a novel fDNA@Fe-Co-SqBMoF bioelectrode for reagentless electrochemical sensing.
• To develop a single-step electrochemical apta-switch (REA) for target analyte detection.
• To demonstrate the applicability of the developed REA for detecting aflatoxin B1 (AFB1).

Main Methods:

• Synthesis and characterization of iron-cobalt squarate bimetallic metal-organic framework (Fe-Co-SqBMoF).
• Fabrication of a redox-active pencil graphite electrode (PGE) modified with Fe-Co-SqBMoF.
• Decoration of the modified electrode with functional DNA (aptamer) to create the fDNA@Fe-Co-SqBMoF bioelectrode.
• Electrochemical characterization using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).

Main Results:

• The fDNA@Fe-Co-SqBMoF bioelectrode exhibited target-responsive, switchable electrochemical signals.
• The developed REA successfully detected aflatoxin B1 (AFB1) in a linear range of 0.7–1000 pg/mL.
• An excellent limit of detection (LOD) of 0.54 pg for AFB1 was achieved.
• The practical applicability was validated in real-world samples like milk and water.

Conclusions:

• The fDNA@Fe-Co-SqBMoF bioelectrode serves as an effective reagentless electrochemical apta-switch.
• This platform demonstrates high sensitivity and selectivity for AFB1 detection.
• The developed method shows significant potential for rapid and reliable on-site analysis of mycotoxins.