Purpose: To improve upon current gluten-detection capabilities, Pi Bioscientific (Pi Bio) has developed and validated a highly rapid diagnostic tool specifically designed to detect deamidated gliadin in foods, on environmental surfaces, and in personal hygiene products.
Methods: Monoclonal antibodies (mAbs) were raised against a synthetic variably deaminated tandem repeat of the peptide recognized by the widely used R5 mAb: L{Q/E}P{Q/E}{Q/E}PFP{Q/E}{Q/E}L{Q/E}P{Q/E}{Q/E}PFP{Q/E}{Q/E}A and chemically deamidated gliadin, screened against a panel of prolamins, purified on a protein G column using FPLC, and used to develop a sandwich lateral flow immunochromatographic (LFD) assay. Sample extraction buffers and running buffers were developed that enable rapid and highly sensitive operation of the LFD. The kit and test method were validated.
Results: The Pi Bio deamidated gluten lateral flow test method had a sensitivity of 0.1 μg protein/swab and 1.0 μg protein/mL of food extract for both deamidated and native gliadin (prolamins) in under 20 min (sample preparation and LFD operation). Specificity analysis indicated cross-reactivity with proteins from teff and selectivity analysis using a panel of problematic matrices revealed no matrix effects on the LOD.
Significance: The development of a highly sensitive and rapid test method capable of accurately detecting trace amounts of deamidated gliadin in under 20 min should aid food manufacturers, contract laboratories and regulatory entities in monitoring for gluten derivatives that have previously proved challenging and will provide more accurate measurements of the gluten content of foods.