A LABEL - FREE IMPEDIMETRIC APTASENSOR FOR THE EVALUATION OF GLUTEN FREE FOODS

Gliadin is a peptide of the gluten proteins responsible for celiac disease. Seeing that there are no available therapies for gluten intolerance, the only treatment of celiac disease is a gluten-free diet. The European Union (Commission Regulation 41/2009) defines that the limit set for all foodstuffs, except infant formula, is lower than 20 mg/kg of gluten in "gluten-free foods" and 20-100 mg/kg of gluten in "very low-gluten content food". Thus the capability to evaluate the presence of gluten in raw materials during manufacturing process represents a key factor for the production of gluten-free products. Thanks to their extreme affinity and sensitivity, aptamers appear as an interesting alternative to antibodies as excellent biorecognition elements to develop reliable and highly sensitive analytical devices. Aptamers are short artificial oligonucleotides selected in vitro that possess high recognition ability to specific target. While antibody-based immunoassay methodologies constitute routine tools for protein detection, the use of aptamer-protein recognition has emerged as a promising alternative to the existing immunochemical tests due to the relatively simple techniques and apparatus required for their preparation and their high stability also in extreme conditions without affecting affinity. In this work we propose the first label free aptasensor for the gluten evaluation based on the Electrochemical Impedance Spectroscopy (EIS) as transduction method. A specific aptamer for the recognition of gliadin was immobilized on gold electrodes and EIS was applied to preliminary characterization of binding kinetic and the analytical parameters of the aptasensor.