The fast growth of celiac disease diagnosis has sparked the production of gluten-free food and the search for reliable methods to detect gluten in foodstuff. In this paper, we report on a microfluidic electronic tongue (e-tongue) capable of detecting trace amounts of gliadin, a protein of gluten, down to 0.005 mg.kg-1 in ethanol solutions, and distinguishing between gluten-free and gluten-containing foodstuff. In some cases it is even possible to determine whether gluten-free foodstuff has been contaminated with gliadin. That was made possible with an e-tongue comprising four sensing units, three of which made of layer-by-layer (LbL) films of semiconducting polymers deposited onto gold interdigitated electrodes placed inside microchannels. Impedance spectroscopy was employed as the principle of detection, and the electrical capacitance data collected with the e-tongue were treated with information visualization techniques with feature selection for optimizing performance. The sensing units are disposable to avoid cross-contamination as gliadin adsorbs irreversibly onto the LbL films according to polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) analysis. Small amounts of material are required to produce the nanostructured films, however, and the e-tongue methodology is promising for low cost, reliable detection of gliadin and other gluten constituents in foodstuff.
Cristiane Margarete Daikuzono, Flavio Makoto Shimizu, Alexandra Manzoli, Antonio Riul, Maria Helena de Oliveira Piazzetta, Angelo Luiz Gobbi, Daniel S Correa, Fernando V. Paulovich, and Osvaldo Novais Oliveira, Jr.
ACS Appl. Mater. Interfaces, Just Accepted Manuscript
Publication Date (Web): May 8, 2017
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