Impedimetric nanoimmunosensor platform for aflatoxin B1 detection in peanuts.

Area of Science:

• Analytical Chemistry
• Biosensors
• Nanotechnology

Background:

• Aflatoxin B1 (AFB1) is a toxic contaminant found in food products.
• Accurate and sensitive detection methods are crucial for food safety and regulatory compliance.
• Existing detection methods can be time-consuming or require complex instrumentation.

Purpose of the Study:

• To develop a novel electrochemical immunosensor for the specific and sensitive detection of AFB1.
• To functionalize iron oxide nanoparticles and immobilize antibodies for enhanced sensing capabilities.
• To evaluate the performance of the developed immunosensor for AFB1 detection in purified samples and real food matrices.

Main Methods:

• Synthesis of amino-functionalized iron oxide nanoparticles (Fe3O4-NH2).
• Immobilization of Fe3O4-NH2 onto mercaptobenzoic acid self-assembly monolayers (SAMs).
• Immobilization of polyclonal antibodies (pAb) on the Fe3O4-NH2-MBA platform.
• Electrochemical characterization using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).
• Performance evaluation including limit of detection (LOD) and limit of quantification (LOQ).

Main Results:

• The immunosensor assembly was confirmed using atomic force microscopy (AFM).
• Electrochemical analysis showed reduced peak currents and increased charge transfer resistance (Rct) upon sensor assembly.
• The interaction with AFB1 blocked electron transfer, enabling specific detection.
• A linear response range of 0.5–30 μg/mL with LOD of 9.47 μg/mL was achieved for purified samples.
• For peanut samples, a LOD of 3.79 μg/mL and LOQ of 11.48 μg/mL were obtained.

Conclusions:

• A simple and effective electrochemical immunosensor for AFB1 detection was successfully developed.
• The nanoimmunosensor demonstrated high sensitivity and specificity for AFB1.
• The proposed method is a valuable tool for ensuring food safety by detecting AFB1 in peanut samples.