The Role of Aryldiazonium Chemistry in Designing Electrochemical Aptasensors for the Detection of Food Contaminants

Abstract

Food safety monitoring assays based on synthetic recognition structures such as aptamers are receiving considerable attention due to their remarkable advantages in terms of their ability to bind to a wide range of target analytes, strong binding affinity, facile manufacturing, and cost-effectiveness. Although aptasensors for food monitoring are still in the development stage, the use of an electrochemical detection route, combined with the wide range of materials available as transducers and the proper immobilization strategy of the aptamer at the transducer surface, can lead to powerful analytical tools. In such a context, employing aryldiazonium salts for the surface derivatization of transducer electrodes serves as a simple, versatile and robust strategy to fine-tune the interface properties and to facilitate the convenient anchoring and stability of the aptamer. By summarizing the most important results disclosed in the last years, this article provides a comprehensive review that emphasizes the contribution of aryldiazonium chemistry in developing electrochemical aptasensors for food safety monitoring.

Critical Design Factors for Electrochemical Aptasensors Based on Target-Induced Conformational Changes: The Case of Small-Molecule Targets

“…The selection of the immobilization strategy must consider the type of aptamer, the electrode material, the analyte’s properties, and also the operating conditions of the final sensor [ 68 ]. This step in the sensor design may influence the binding affinity, the stability, and the accessibility of surface-confined aptamers, the non-specific adsorption, and finally the overall performance of the final sensor [ 1 , 68 ]. Among the different methods applied for aptamers’ immobilization at the electrode surface, the covalent binding is the most common.…”

“…Over the last decades, biosensor technology has been proving its capability to complement or replace many of the complicated, relatively expensive, and time-consuming traditional analytical methods [ 1 , 2 , 3 , 4 ]. More recently, the use of nucleic acid aptamers as biorecognition elements has brought numerous advantages in comparison with the enzymes or antibodies commonly used in biosensors, such as smaller size, better stability, reversible binding ability, simple chemical modification, and a lower cost [ 4 , 5 , 6 , 7 ].…”

“…Moreover, unlike antibodies, aptamers can be obtained through chemical synthesis without batch-to-batch variation and free of microbial contamination [ 8 , 9 , 10 ]. The high specificity of aptamers for their molecular targets and their versatility for different types of analytical platforms has stimulated the development of a broad variety of biosensors based on aptamers (aptasensors) for domains such as medicine, environmental monitoring, or food safety [ 1 , 2 , 11 ]. In particular, the important progress observed in the electrochemical aptasensors’ development could be assigned to the simplicity and degree of control of the electrochemical transduction methods, the ease of aptamers’ integration in the electrochemical platforms, and the possibility to achieve ultrasensitive detection at a lower cost [ 11 , 12 ].…”

“…Alongside the aptamer selection step, the sensor design must also consider the proper incorporation of these molecules in the biorecognition layer [ 19 ]. The choice of an adequate immobilization strategy is important in respect with both the sensor performance, but also regarding basic requirements such as preserving the biological activity, stability, or the accessibility of the bioreceptor molecules [ 1 , 20 ]. The scope of this review was to provide a short overview on the challenges in selecting the aptamers with optimal binding properties for small molecules, and to offer guidance on choosing the appropriate solutions for designing electrochemical aptasensors for these types of targets.…”

A Fluorescence Kinetic-Based Aptasensor Employing Stilbene Isomerization for Detection of Thrombin

“…In particular, aptamers present unique adaptive binding feature [15]. Currently, aptamers are seen as a new kind of biorecognition element used in various types of biosensors, namely, aptasensors [16]. Aptasensors including electrochemical, optical, and electrical approaches have demonstrated advantages of being sensitive, robust, stable, rapid, and selective [17][18][19][20][21][22].…”