A sensitive electrochemical molecularly-imprinted sensor was developed for the detection of aflatoxin B1 (AFB1), by electropolymerization of p-aminothiophenol-functionalized gold nanoparticles in the presence of AFB1 as a template molecule. The extraction of the template leads to the formation of cavities that are able to specifically recognize and bind AFB1 through π-π interactions between AFB1 molecules and aniline moities. The performance of the developed sensor for the detection of AFB1 was investigated by linear sweep voltammetry using a hexacyanoferrate/hexacyanoferrite solution as a redox probe, the electron transfer rate increasing when the concentration of AFB1 increases, due to a p-doping effect. The molecularly-imprinted sensor exhibits a broad linear range, between 3.2 fM and 3.2 µM, and a quantification limit of 3 fM. Compared to the non-imprinted sensor, the imprinting factor was found to be 10. Selectivity studies were also performed towards the binding of other aflatoxins and ochratoxin A, proving good selectivity.

This paper presents the fabrication of a molecularly imprinting sol–gel hybrid film by the one-step electrodeposition of the constitutional individuals including chitosan (CS), phenyltrimethoxysilane (PTMS), in situ formed gold nanoparticles (AuNPs) and template p-nitrophenol (p-NP). The electrodeposition was triggered by applying an optimal potential at −0.30 V vs. SCE, leading to the formation of the p-NP imprinting CS/PTMS/AuNPs hybrid film on a glassy carbon electrode (GCE) with a roughly architectural and conductive nature, as revealed by scanning electron microscopy and electrochemical impedance analysis. The mechanism of the hybrid film formation was discussed accordingly. Upon complete removal of the template molecules assisted by cyclic voltammetry, the p-NP imprinted film modified electrode exhibited differential pulse voltammetric (DPV) responses to p-NP in a linear range from 3.0 × 10⁻⁸ to 3.5 × 10⁻⁴ M with a detection limit of 5.0 × 10⁻⁹ M. The selectivity and reusability of the sensor was demonstrated by discriminating the p-NP response from its analogues and successive rebinding/debinding cycles, respectively. The methodology is extendable as a simple and general platform for developing hybrid film sensors for the specific determination of various electrochemically active species.