Impedimetric Polyaniline-Based Aptasensor for Aflatoxin B1 Determination in Agricultural Products

Abstract

An impedimetric aptasensor based on a polyaniline (PAni) support matrix is developed through the surface modification of a screen-printed carbon electrode (SPE) for aflatoxin B1 (AFB1) detection in foodstuffs and feedstuffs for food safety. The PAni is synthesized with the chemical oxidation method and characterized with potentiostat/galvanostat, FTIR, and UV–vis spectroscopy techniques. The stepwise fabrication procedure of the PAni-based aptasensor is characterized by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods. The impedimetric aptasensor is optimized using the EIS technique, and its feasibility of detecting AFB1 in real sample matrices is evaluated via a recovery study in spiked foodstuffs and feedstuffs, such as pistachio nuts, cinnamons, cloves, corn, and soybeans, with a good recovery percentage, ranging from 87.9% to 94.7%. The charge transfer resistance (RCT) at the aptasensor interface increases linearly with the AFB1 concentration in the range of 3 × 10−2 nM to 8 × 10−2 nM, with a regression coefficient (R2) value of 0.9991 and detection limit of 0.01 nM. The proposed aptasensor is highly selective towards AFB1 and partially selective to AFB2 and ochratoxin A (OTA) due to their similar structures that differ only at the carbon–carbon double bond located at C8 and C9 and the large molecule size of OTA.

Recent Progress of Electrochemical Aptasensors toward AFB1 Detection (2018–2023)

“…Moreover, controlled polymerization allows for the formation of polymer structures that are not only similar on the entire WE surface, but also make possible the incorporation of different nanomaterials, which improves the accuracy [47]. Polyheteroaromatic polymers, such as polypyrrole, polyaniline (PANI), and their derivatives, have attracted a lot of attention lately because of their possible application toward electrochemical detection [48][49][50]. Being one of the most versatile conductive polymers, PANI was used in order to increase the electroconductive properties of a platform developed for AFB1 aptasensing in wine with very low LODs, down to 0.002 fg/mL [51].…”

“…Multiple label-free electrochemical aptasensors based on carbon nanotubes [82,87], graphene oxide [80], reduced graphene oxide [55,77,82,85,87], AuNPs [42,76,77,87] or Aubased materials [51,83,86,90], polymers [49,77,80], and MOFs [79] have been reported recently.…”