Design of novel hybrid probe based on double recognition of aptamer-molecularly imprinted polymer-gold nanoparticles for food allergen gliadin sensing.

Abstract

Gliadins are allergenic proteins that can pose various risks to human health and are found in high amounts in the most commonly consumed foods. Gliadin, a component of gluten, triggers oxidative stress in celiac disease. Using sensitive analytical methods, especially in foods containing high amounts of these proteins, is crucial for food safety. Aptamer-based biosensors are widely preferred in electroanalytical methods. One of the promising approaches regarding biosensors is the studies in which aptamer-based sensors are combined with molecularly imprinted polymers. The antibody-like binding and ability of MIP to distinguish between molecules increases the method's selectivity. Using a platform modified with aptamer and molecularly imprinted polymer hybrid (MIP) as a new synthetic receptor film, this study presents a selective and sensitive label-free aptasensor for detecting a food allergy gliadin. For this purpose, screen printed gold electrode was used. The electrode surface was electrochemically coated with gold nanoparticles to bind the aptamer to the surface; then the aptamer-gliadin complex was dripped onto the surface and adhered to it, then, o-phenylene diamine monomer was used to synthesize a MIP surface. Gliadin was determined by using differential pulse voltammetry (DPV) in a wide range from 0.25 fg/mL to 1000 pg/mL. The developed method calculated LOD for gliadin determination as 0.011 fg/mL and LOQ as 0.034 fg/mL. The devised aptasensor was not only capable to the discrimination of the commonly found allergen compounds such as bovine serum albumin (BSA), casein, and ara-H1, but also it could detect the gliadin in spiked real samples such as gluten-free bread, crackers, cookies and brown rice cakes samples in the high recovery range of 98.1-104.6 %. The method could be a promising candidate for the sensitive determination of several allergens in food sample analysis.