AuNPs-functionalized PANABA-MWCNTs nanocomposite-based impedimetric immunosensor for 2,4-dichlorophenoxy acetic acid...

Area of Science:

• Electrochemistry
• Biosensors
• Environmental Science

Background:

• 2,4-Dichlorophenoxy Acetic Acid (2,4-D) is a widely used herbicide.
• Sensitive and reliable detection methods for 2,4-D are crucial for environmental monitoring and food safety.
• Existing detection methods may lack sensitivity, speed, or cost-effectiveness.

Purpose of the Study:

• To develop a label-free impedimetric immunosensor for the detection of 2,4-D.
• To utilize a novel nanocomposite material for enhanced sensor performance.
• To validate the sensor's performance in standard solutions and real-world samples.

Main Methods:

• Electropolymerization of poly-(aniline-co-3-aminobenzoic acid) (PANABA) on a multi-walled carbon nanotubes-based screen printed electrode.
• Immobilization of anti-2,4-D antibody onto a gold nanoparticles (AuNPs)-PANABA-MWCNTs nanocomposite.
• Electrochemical Impedance Spectroscopy (EIS) using Fe(CN)₆^3-/4- as a redox probe for impedimetric measurements.
• Synthesis of nanocomposite via electrochemical polymerization of aniline and 3-aminobenzoic acid in the presence of AuNPs.

Main Results:

• The developed immunosensor demonstrated a wide linearity range for 2,4-D detection from 1 to 100 ppb.
• Achieved good repeatability with a Relative Standard Deviation (RSD) of 6%.
• Exhibited excellent stability and a low Limit of Detection (LOD) of 0.3 ppb, below herbicide emission limits.

Conclusions:

• The novel impedimetric immunosensor based on AuNPs-PANABA-MWCNTs nanocomposite is effective for sensitive and label-free 2,4-D detection.
• The enhanced conductivity of the nanocomposite contributes to improved antigen detection sensitivity.
• The sensor shows promise for practical applications in monitoring 2,4-D levels in environmental and agricultural samples.