A portable electrochemiluminescence aptasensor for ß-lactoglobulin detection.

Cow's milk allergy is one of the most common food allergies in children with a prevalence of around 2.5%. Milk contains several allergens; the main ones are caseins and ß-lactoglobulin (ß-LG). At regulatory level, ß-LG is not explicitly named, but milk is included in the list of substances or products causing allergies or intolerances. Hence, the presence of ß-LG can be a useful marker for determining the presence of milk in food. In this work, we present an aptasensor based on electrochemiluminescence (ECL) for the quantification of ß-LG in real food matrices displaying integrated advantages consisting of high specificity, good sensitivity, portability, and cost effectiveness. The performance and applicability of this sensor were tested by analyzing a sample of skimmed milk and an oat-based drink proposed as a vegetable substitute for milk of animal origin. We obtained a linear correlation between the intensity of the signal and the concentration of ß-LG standard solutions (y = x * 0.00653 + 1.038, R2 = 0.99). The limit of detection (LOD) and the limit of quantification (LOQ) were found to be 1.36 and 4.55 µg L-1, respectively.

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

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.