Electrochemical Biosensors for the Determination of Toxic Substances Related to Food Safety Developed in South America: Mycotoxins and Herbicides

Abstract

The goal of achieving food safety and quality has become increasingly important in relevant areas. The achievement of this objective includes a significant effort in different areas related to the production of raw materials, storage, transportation, etc. One of the central areas in the verification of food safety and food quality control is related to the analysis of food components and, in particular, possible toxic substances that they may contain. Therefore, the demand for appropriate methods for the determination of these substances is increasingly demanding. Thus, not only is accuracy and precision sought in the results of the analysis, but also the speed, simplicity and lowering of costs. In this way, electrochemical techniques and, particularly, electrochemical biosensors have emerged in recent times as good candidates to satisfy such requirements. This review summarizes the advances made in research and development centers located in South American countries related to the development of electrochemical biosensors for the determination of toxic substances present in foods, particularly mycotoxins and herbicides.

Immobilized Enzymes in Biosensor Applications

“…Enzyme-based amperometric biosensors have been widely studied, due to advantages such as ease in miniaturization, robustness, and the capability to operate with small sample volumes of rather complex matrices [16,17]. Amperometric enzyme biosensors have been developed through three generations, according to the electron transfer methods that have been used for the measurement of the biochemical reaction [18]. Nowadays, several kinds of commercial enzyme-based amperometric biosensors are accessible for measuring glucose, lactate, alcohol, etc., by using oxidases (i.e., glucose oxidase, lactate oxidase, alcohol oxidase, etc.)…”

“…The main advantages of first-generation amperometric biosensors are their high sensitivity and the low response time (around one second). However, drawbacks such as the requirement of coenzymes and the high potential for operation, fouling transducers surface due to prolonged use, and an error that relies on electron acceptor concentration (such as dissolved molecular oxygen concentration) may limit its usage in biological systems [18,19,20]. In order to eliminate oxygen dependency, second-generation biosensors use a mediator (electron acceptor), instead of oxygen, to transport the electrons to the electrode.…”

“…In this principle, the mediator is reduced by the electron generated from the enzymatic reaction, and then is finally oxidized at the electrode, resulting in electron transfer to the electrode. Although the second-generation biosensor is oxygen-independent, it suffers from mediator leaching and interference, due to redox mediator selectivity [18,19,21]. Hence, the third-generation biosensor was developed to solve that issue.…”

Electrochemical Immunosensor for Detection of Aflatoxin B1 Based on Indirect Competitive ELISA

“…From the results, the %RSD of the developed immunosensor was 4.78% and 2.71% for reproducibility and repeatability, respectively. However, electrochemical immunosensors suffer from insufficient stability over extended period of time [ 37 ]. In this study, the use of EDC–NHS and nanocomposite of MWCNT/CS had a positive effect on the immobilization of the antibody on the active site of sensor.…”

Food Safety Analysis Using Electrochemical Biosensors

“…Antibodies or aptamers can be produced for several toxins, bacterial species, pesticides, herbicides, and antibiotic residues, as well as for nontoxic substances, such as proteins and other small molecules for construction of an electrochemical biosensor. These substances can be easily detected using these biosensors as long as they are foreign to the immunizing species [ 46 ]. The high affinity of the biorecognition elements for their target analytes allowed the development of very sensitive and specific electrochemical biosensors.…”