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

In this work, we developed an impedimetric label-free immunosensor for the detection of 2,4-Dichlorophenoxy Acetic Acid (2,4-D) herbicide either in standard solution and spiked real samples. For this purpose, we prepared by electropolymerization a conductive polymer poly-(aniline-co-3-aminobenzoic acid) (PANABA) then we immobilized anti-2,4-D antibody onto a nanocomposite AuNPs-PANABA-MWCNTs employing the carboxylic moieties as anchor sites. The nanocomposite was synthesized by electrochemical polymerization of aniline and 3-aminobenzoic acid, in the presence of a dispersion of gold nanoparticles, onto a multi-walled carbon nanotubes-based screen printed electrode. Aniline-based copolymer, modified with the nanomaterials, allowed to enhance the electrode conductivity thus obtaining a more sensitive antigen detection. The impedimetric measurements were carried out by electrochemical impedance spectroscopy (EIS) in faradic condition by using Fe(CN)6(3-/4-) as redox probe.