Quantitative gluten testing must usually be carried out in a laboratory setting due to the use of technical equipment and reagents. Responding to a need for more simple and affordable methods, researchers have developed a gluten-sensitive colour-changing biosensor.
The biosensor was developed to change colour in the presence of gliadin, which is one of the two main protein components of gluten. The biosensor comprises gold nanoparticles coated with aptamers, special molecules that stick to gliadin. When there is no gliadin present, the aptamers keep the nanoparticles apart, preventing them from clumping together. When gliadin is present, with the addition of sodium chloride, the nanoparticles clump together, creating a colour change. The degree of colour change is proportional to the amount of gliadin (and therefore gluten) that is present.
Under optimised conditions, the biosensor demonstrated sensitivity to the detection limit of 32.1 ng mL-1 and maintained reliable performance when applied to real foods, including gluten-free bread, cookies, and pasta.
The study authors maintain that due to its simplicity, selectivity, speed, and cost-effectiveness, the biosensor represents a significant advancement over existing gluten detection methods. They also suggest the biosensor design could be modified to detect other food allergens or protein toxins by changing the aptamers used.
Reference: Seung Hwan Ham et al. “A label-free aptamer-based colorimetric biosensor for rapid gliadin detection in foods: a focus on pasta, bread and cookies”. Analytical Methods, 2024. Vol. 16(3) pp 449-457. DOI: 10.1039/d3ay01695a.
