Functionalized TiO2 Nanotube Platform for Gliadin Electroanalysis

The present paper presents a gliadin detection method. This method is based on a modified Ti electrode. Modification was performed by a simple and cheap anodization. Then, a layer of graphene oxide was added, and gliadin antibody was fixed on the electrode surface. Using this complex system, electrochemical impedance spectroscopy was used for gliadin detection. Solutions with known gliadin (a fraction from gluten) content were used for analysis. Impedance measured at a certain frequency and coating resistance were analyzed. Better results (good linearity and lower detection limit) were obtained by plotting impedance at a certain frequency versus gliadin concentration. Coating resistance was proved to be in linear dependency with gliadin concentration only at lower concentrations. This system based on titanium nanostructured electrode has the potential to be used for gluten contamination detection from foods.

X6: A Novel Antibody for Potential Use in Gluten Quantification

Gliadin is a fraction of gluten, known to trigger celiac disease in susceptible people. To date, the life-long gluten-free diet is used for the prevention of this disease. Hence, methods for gluten control in foods are of significant importance. Being one of the most-used methods used for this purpose, ELISA should use high-affinity antibodies to gliadin peptides involved into celiac process. This study investigates the characteristics of a novel anti-gliadin antibody X6. We found the QXQPFPXP site to be a recognized epitope that provides specific binding of the antibody to cereal prolamins involved in celiac disease manifestation. A specificity study using immunoblotting shows the recognition of wheat, barley and rye proteins—as well as α-gliadin homologs from non-edible cereals (Dasypyrum villosum). Reactivity to avenin was less pronounced, as this protein does not contain the PFP motif most critical for antibody recognition. The proteins of Zea mays and Setaria italica were not recognized by X6. X6-based ELISA highly correlated with R5 and G12, which are Codex Alimentarius standards in the quantitative assessment of gluten content (Pearson’s R = 0.86 and 0.87, respectively). Qualitative assessment revealed no significant differences between R5 and G12 and X6.