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

Maria Freitas,Cristina Delerue-Matos,Henri P A Nouws

doi:10.3390/bios11110426

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.

Highlights

Awareness about food allergies has risen globally because of the increase of the number of reported allergic occurrences [1]
The related symptoms are generally due to the action of immunoglobulin E (IgE), varying from mild to severe systemic reactions, namely cutaneous, digestive and/or cardiovascular complications, and respiratory difficulties with anaphylactic shock that require emergency treatments [2,3]
There are only a few works regarding the development of electrochemical immunosensors applying Quantum dots (QDs) as detection labels to ensure food safety: a 3D printed microcell to evaluate adulterated ewe/goat’s cheese species with cow’s milk [28], a lab-on-a-membrane device to detect milk adulteration [29], direct culture-free analysis of Salmonella in milk [30], biointerface platforms for the food toxin aflatoxin B1 [31,32] and determination of the mycotoxin fumonosin in corn [33]

Summary

Introduction

Awareness about food allergies has risen globally because of the increase of the number of reported allergic occurrences [1]. There are only a few works regarding the development of electrochemical immunosensors applying QDs as detection labels to ensure food safety: a 3D printed microcell to evaluate adulterated ewe/goat’s cheese species with cow’s milk [28], a lab-on-a-membrane device to detect milk adulteration [29], direct culture-free analysis of Salmonella in milk [30], biointerface platforms for the food toxin aflatoxin B1 [31,32] and determination of the mycotoxin fumonosin in corn [33] In this context, QDs constitute an alternative to the traditional enzymatic probes, avoiding their major drawbacks (e.g., thermal instability, substrate addition, cross-reactivity with sample components) [34,35]. The resulting peak current intensity (ip) increases with increasing target analyte concentration and was quantitatively related with the presence of Ara h 1

Apparatus and Electrodes

Reagents and Solutions

Method Performance

Ara h 1 Determination in Food Samples

Findings

Conclusions