An Effective Label-Free Electrochemical Aptasensor Based on Gold Nanoparticles for Gluten Detection

Abstract

Nanomaterials can be used to modify electrodes and improve the conductivity and the performance of electrochemical sensors. Among various nanomaterials, gold-based nanostructures have been used as an anchoring platform for the functionalization of biosensor surfaces. One of the main advantages of using gold for the modification of electrodes is its great affinity for thiol-containing molecules, such as proteins, forming a strong Au-S bond. In this work, we present an impedimetric biosensor based on gold nanoparticles and a truncated aptamer for the quantification of gluten in hydrolyzed matrices such as beer and soy sauce. A good relationship between the Rct values and PWG-Gliadin concentration was found in the range between 0.1–1 mg L−1 of gliadin (corresponding to 0.2–2 mg L−1 of gluten) with a limit of detection of 0.05 mg L−1 of gliadin (corresponding to 0.1 mg L−1 of gluten). The label-free assay was also successfully applied for the determination of real food samples.

Aptamer-Based Electrochemical Biosensors for the Detection of Salmonella: A Scoping Review

“…This finding was in agreement with other literature that reported AuNPs as the most standing nanomaterials utilized for modifying working electrodes in numerous types of electrochemical biosensors [ 75 , 76 ]. AuNPs exhibit excellent characteristics, including a high surface-to-volume ratio and surface energy due to their nanoscale size, and enhance the electron movement between redox species and the electrode surface [ 77 , 78 , 79 ]. Moreover, AuNPs have versatility in conjugation with various biomolecules without affecting their biochemical characteristics [ 80 ].…”

Recent Advances in Electrochemical Sensing Strategies for Food Allergen Detection

“…Recently, the Toniolo group reported a label-free impedimetric aptasensor for gliadin, based on AuNPs as the immobilizing platform and on Gli-4 truncated aptamer (Gli-4T) with high affinity with the target [ 130 ]. AuNPs provided not only a stable immobilization for Gli-4T, but, as usual, an improvement in the electron transfer from and to the electrode and in the active surface area [ 45 ].…”

“… Scheme of the aptasensor design and sensing strategy: after the electrochemical deposition of AuNPs streptavidin was immobilized on the working electrode, then a solution of BSA and sorbitol was used to block the surface; subsequently, the biotinylated aptamer was immobilized, and after a final step of blocking with biotin, the sensor was ready to use. Reprinted from [ 130 ]. …”

Hemolysis-Inspired, Highly Sensitive, Label-Free IgM Detection Using Erythrocyte Membrane-Functionalized Nanomechanical Resonators

“…However, these labeling methods cause false-positive/negative occurrences in biological assays due to alterations in physicochemical or intermolecular binding properties [ 22 , 23 ]. To solve this problem, label-free methods for biomolecular detection have been developed, such as electrochemical [ 24 , 25 , 26 ], surface plasmon resonance [ 27 , 28 ], and nanowell assay [ 29 , 30 , 31 ]. The label-free immunoassay methods are attracting attention because of their advantages, such as easy fabrication [ 32 ] and low cost [ 33 ], while excluding the effect of the labels [ 34 ].…”