Voltammetric Immunosensor to Track a Major Peanut Allergen (Ara h 1) in Food Products Employing Quantum Dot Labels

Abstract

Tracking unreported allergens in commercial foods can avoid acute allergic reactions. A 2-step electrochemical immunosensor was developed for the analysis of the peanut allergen Ara h 1 in a 1-h assay (<15 min hands-on time). Bare screen-printed carbon electrodes (SPCE) were used as transducers and monoclonal capture and detection antibodies were applied in a sandwich-type immunoassay. The short assay time was achieved by previously combining the target analyte and the detection antibody. Core/shell CdSe@ZnS Quantum Dots were used as electroactive label for the detection of the immunological interaction by differential pulse anodic stripping voltammetry. A linear range between 25 and 1000 ng·mL−1 (LOD = 3.5 ng·mL−1), an adequate precision of the method (Vx0 ≈ 6%), and a sensitivity of 23.0 nA·mL·ng−1·cm−2 were achieved. The immunosensor was able to detect Ara h 1 in a spiked allergen-free product down to 0.05% (m/m) of peanut. Commercial organic farming cookies and cereal and protein bars were tested to track and quantify Ara h 1. The results were validated by comparison with an ELISA kit.

Tracking Arachis hypogaea Allergen in Pre-Packaged Foodstuff: A Nanodiamond-Based Electrochemical Biosensing Approach

“…Ara h 1 was also quantified in a commercial raw peanut sample. The obtained result (4.29 ± 0.16 mg·g −1 ) is lower compared to our previously reported electrochemical immunosensors [ 18 , 19 ].…”

“…The present work reports an SPCE/ND platform with an increased electroactive area, allowing the screening of Ara h 1 in peanut-containing foodstuff and products thereof, with highly accurate results, able to detect at least 0.10% (m/m) of peanut. Compared to previously published electrochemical immunosensors for Ara h 1 quantification ( Table 3 ), several nanomaterials such as SWCNT [ 16 ], gold nanoparticles [ 18 ], and Quantum Dots [ 19 ] were employed to improve the sensor’s performance. Nonetheless, their main drawback is the lack of proficiency to validate the presence or absence of traces in commercially available products and/or distinguishing between the matrix effect and the presence of low amounts.…”

“…Regarding affordable biosensing devices for food allergen concerns, immunosensors are prominently featured [ 13 , 14 ]. Hence, tracking peanuts in pre-packaged foods using electrochemical immunoassays by employing self-assembled monolayers and/or nano- and micromaterials has been accomplished and described for Ara h 1 [ 15 , 16 , 17 , 18 , 19 ]. The reported strategies contribute to the progress of miniaturized and portable analytical platforms and include an impedance immunosensor developed using conventional gold electrodes functionalized with a self-assembled monolayer (11-mercaptoundecanoic acid) [ 15 ], a functionalized single-walled carbon nanotubes (SWCNT)-based junction sensor (gold assembly on silicon wafers) [ 16 ], an amperometric magnetoimmunosensing platform using carboxylic-acid-modified Magnetic Beads (MBs) using bare screen-printed carbon electrodes (SPCE) [ 17 ], and a gold-nanoparticle-coated SPCE sandwich-type immunosensor, able to detect Ara h 1 in samples containing 0.1% ( m / m ) of peanut, applied to the analysis of cookies and chocolate [ 18 ].…”

“…Recently, quantum dots were employed as the electroactive label to develop a voltammetric immunosensor that employed bare SPCEs as a simple and non-modified transducer. In this work, through immunological interaction, the target analyte was detected in commercial organic farming cookies (down to 0.05% ( m / m ) of peanut) [ 19 ].…”

Sensors for Environmental Monitoring and Food Safety

“…A two-step electrochemical immunosensor was developed for the analysis of the peanut allergen Ara h 1 in a 1 h assay [ 8 ]. Bare screen-printed carbon electrodes were utilized as the transducer.…”