Design of Pyrrole-Based Gate-Controlled Molecular Junctions Optimized for Single-Molecule Aflatoxin B1 Detection.

Area of Science:

• Materials Science
• Nanotechnology
• Food Safety

Background:

• Aflatoxins pose a significant global food contamination risk due to their toxicity.
• Current aflatoxin detection methods, primarily biosensing, limit widespread monitoring in the agri-food chain.
• There is a critical need for sensitive and pervasive aflatoxin detection technologies.

Purpose of the Study:

• To investigate a pyrrole-based Molecular Field Effect Transistor (MolFET) as a single-molecule sensor for aflatoxin detection.
• To theoretically explain the gate-tuned current modulation mechanism for amperometric aflatoxin sensing.
• To demonstrate the enhancement of sensor performance using a suitable gate voltage.

Main Methods:

• Utilized ab initio atomistic calculations to model a pyrrole-based MolFET.
• Performed theoretical analysis of chemical-physical principles governing gate-tuned current modulation.
• Conducted simulations to support theoretical insights and validate sensor performance.

Main Results:

• Demonstrated that a gate voltage significantly enhances the MolFET's performance for aflatoxin detection.
• The gating effect increased aflatoxin-induced current modulation from 100% to over 103–104%.
• Observed a two-order-of-magnitude decrease in current (μA to nA range) in the presence of aflatoxin B1.

Conclusions:

• A pyrrole-based MolFET can serve as a sensitive single-molecule sensor for aflatoxin detection.
• Gate voltage is a crucial parameter for optimizing MolFET-based aflatoxin sensor performance.
• This research supports the development of miniaturized FET electrical detection for pervasive aflatoxin monitoring.