Electrochemical Affinity Biosensors in Food Safety

Abstract

Safety and quality are key issues of today's food industry. Since the food chain is becoming more and more complex, powerful analytical methods are required to verify the performance of food safety and quality systems. Indeed, such methods require high sensitivity, selectivity, ability for rapid implementation and capability of automatic screening. Electroanalytical chemistry has, for decades, played a relevant role in food safety and quality assessment, taking more and more significance over time in the solution of analytical problems. At present, the implementation of electrochemical methods in the food is evident. This is in a large part due to the relevant results obtained by combining the attractive advantages of electrochemical transduction strategies (in terms of relatively simple hardware, versatility, interface with automatic logging and feasibility of application outside the laboratory environment) with those from biosensors technology. Important examples of enzyme electrochemical biosensors are those dedicated to the determination of glucose, alcohol or cholesterol are important examples. In addition, other types of different electrochemical biosensing approaches have emerged strongly in the last years. Among these, the strategies involving affinity interactions have been shown to possess a large number of applications. Therefore, electrochemical immunosensors and DNA-based biosensors have been widely used to determine major and minor components in foodstuffs, providing sufficient data to evaluate food freshness, the quality of raw materials, or the origin of samples, as well as to determine a variety of compounds at trace levels related to food safety such as micotoxins, allergens, drugs residues or pathogen microorganisms. This review discusses some critical examples of the latest advances in this area, pointing out relevant methodologies related to the measurement techniques, including the use of nanostructured electrodes and strategies for signal amplification.

Comparative Assessment of Affinity-Based Techniques for Oriented Antibody Immobilization towards Immunosensor Performance Optimization

“…Ιmmunosensors are affinity-based assays that feature prominently as effective tools for the quantification of the amount of antibodies or antigens in complex samples. Irrespectively of whether it is the antibody or the antigen that is immobilized on the transducer surface, the strong binding forces that develop allow the detection of the target analyte with high sensitivity and specificity [1], making them very attractive for applications in a diverse range of fields such as food safety [2,3], medical diagnostics [4,5], and environmental monitoring [6,7].…”

Molecular Modeling and Simulation Tools in the Development of Peptide-Based Biosensors for Mycotoxin Detection: Example of Ochratoxin

“…Following the substrate selection, several strategies to immobilize peptides on a variety of materials are available and have been previously reviewed [ 57 ]. Surface immobilization of peptides are often achieved via: (1) physical adsorption; (2) covalent attachment via chemical activation of functional groups on the surface and functional groups on the peptide; (3) molecular entrapment approaches; or (4) linkers-like affinity tags such as polyhistidine-tag (6-His), biotinylation of peptide receptors and their subsequent immobilization via streptavidin-coated supports, and Watson-Crick paired DNA-directed immobilization [ 12 , 14 , 35 , 58 , 59 ]. Ideally, the support substrates onto which the peptides are immobilized should minimally interact with the peptide, should orient the binding site within the peptide towards the analyte without any steric hindrance, and not interfere with the peptide’s mycotoxin binding properties.…”

Advantages of Carbon Nanomaterials in Electrochemical Aptasensors for Food Analysis

“…A variety of strategies can be pursued to ensure adequate stability and surface coverage by aptamer while maintaining high binding affinity as displayed in solution, including: chemisorption of thiolated aptamers on Au electrodes; attachment of biotinylated aptamer to avidin‐modified sensor surfaces; click chemistry immobilisation of azide‐ended aptamer to alkyne‐modified surfaces; covalent immobilisation of amine‐ended aptamers by amide coupling to functionalized surfaces displaying carboxyl groups, covalent immobilisation of amine‐ended aptamer to functionalized surfaces displaying amine groups using glutaraldehyde etc. These strategies have been nicely illustrated in several reviews . Aptasensor design might include spacers to enable the conformational freedom of the aptamer or various nanomaterials and nanocomposites with different roles.…”