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

Abstract

Food contaminants represent possible threats to humans and animals as severe food safety hazards. Prolonged exposure to contaminated food often leads to chronic diseases such as cancer, kidney or liver failure, immunosuppression, or genotoxicity. Aflatoxins are naturally produced by strains of the fungi species Aspergillus, which is one of the most critical and poisonous food contaminants worldwide. Given the high percentage of contaminated food products, traditional detection methods often prove inadequate. Thus, it becomes imperative to develop fast, accurate, and easy-to-use analytical methods to enable safe food products and good practices policies. Focusing on the recent progress (2018-2023) of electrochemical aptasensors for aflatoxin B1 (AFB1) detection in food and beverage samples, without pretending to be exhaustive, we present an overview of the most important label-free and labeled sensing strategies. Simultaneous and competitive aptamer-based strategies are also discussed. The aptasensors are summarized in tabular format according to the detection mode. Sample treatments performed prior analysis are discussed. Emphasis was placed on the nanomaterials used in the aptasensors' design for aptamer-tailored immobilization and/or signal amplification. The advantages and limitations of AFB1 electrochemical aptasensors for field detection are presented.

Keywords: aflatoxin B1; aptamer; electrochemical; label-free aptasensors; labeled.

Figure 1

(A) Literature report of AFB1 detection based on aptamers (2013–2023) and (B) the distribution of electrochemical methods out of all reported methods (Scopus database).

Figure 2

Schematic representation of main electrochemical aptasensor designs (label-free, labeled, competitive, and simultaneous) and the detection methods (EIS—electrochemical impedance spectroscopy; DPV—differential pulse voltammetry; SWV—square wave voltammetry; amperometry, where “a” and “b” represent the signal change upon target interaction). Created with Biorender.com.

Figure 3

Label-free electrochemical aptasensor based on (A) COOH–GO–COOH–MWNT/pDA/AuNPs (reprinted from [87] with permission from the Royal Society of Chemistry) and (B) Fe₃O₄@Au-Apt nanospheres (reprinted with permission from [51]).

Figure 4

(A) Labeled aptasensor based on Fc signal tag incorporated in HPCS through a layer-by-layer assembly and tetrahedral DNA nanostructures (TDNs). Reprinted with permission from [96]. (B) Ratiometric-labeled aptasensor following (a) the signal reaction process of HP and linear-HP (I and II) on a single sensing interface of the aptasensor and (b) the reaction process of HP on the surface of the aptasensor. Reprinted with permission from [98].

Figure 5

(A) CeO₂/Fe-porphyrinic MOF composite aptasensor based on aptamer–target displacement mechanism. Reprinted with permission from [105]. (B) Ratiometric DECA method based on HCR signal amplification. Reprinted with permission from [109].

Figure 6

Simultaneous electrochemical analysis of AFB1 and OTA by a competitive ratiometric approach using Fc and MB labels as target indicators and AQ as a reference signal. The schematic representation of the hDNA (A) and ssDNA (B) configurations of the capture probe. Reprinted with permission from [115].