Patterning Large-Scale Nanostructured Microarrays on Coverslip for Sensitive Plasmonic Detection of Aqueous Gliadin Traces

Rapid Gluten Allergen Detection Using an Integrated Photoimaging Assay and Ionic Liquid Extraction Sensor

In recent years, food allergies and food sensitivities have remained critical public health problems that affect approximately 15% of the global population. Wheat is a major food source worldwide, but it is also a common food allergen. Celiac disease is chronic immune-mediated enteropathy triggered by exposure to dietary gluten in genetically predisposed individuals; it can be treated only through strict gluten avoidance. Therefore, rapid gluten detection is crucial for protecting the health of patients. Gluten contains two primary water-insoluble proteins: gliadin and glutenin. Gliadin is a key contributor to celiac disease and poses challenges for sample pretreatment owing to its insolubility, thereby reducing the accuracy and sensitivity of detection systems. Rapid sample processing is a critical problem in gliadin detection. In this report, we developed a gliadin sensor system called the integrated food allergy and microorganism sensor (iFAMs). The iFAMs comprises a gliadin lateral flow chip, a one-pot extraction solution, and an image assay app. The iFAMs enables gliadin extraction and detection in under 2 min with high sensitivity (0.04 mg/kg for gliadin, lower than the regulatory limit of 20 mg/kg). Users can easily measure gluten concentrations in samples and quantify gliadin levels using the smartphone-based image assay app. In samples collected from restaurants, the iFAMs successfully detected hidden gluten within "gluten-free" food items. The compact size and user-friendly design of the iFAMs render it suitable for not only consumers but also clinicians, food industries, and regulators to enhance food safety.

Parylene Double-Layer Coated Screen-Printed Carbon Electrode for Label-Free and Reagentless Capacitive Aptasensing of Gliadin

Celiac patients are required to strictly adhere to a gluten-free diet because even trace amounts of gluten can damage their small intestine and leading to serious complications. Despite increased awareness, gluten can still be present in products due to cross-contamination or hidden ingredients, making regular monitoring essential. With the goal of guaranteeing food safety for consuming labeled gluten-free products, a capacitive aptasensor was constructed to target gliadin, the main allergic gluten protein for celiac disease. The success of capacitive aptasensing was primarily realized by coating a Parylene double-layer (1000 nm Parylene C at the bottom with 400 nm Parylene AM on top) on the electrode surface to ensure both high insulation quality and abundant reactive amino functionalities. Under the optimal concentration of aptamer (5 μM) used for immobilization, a strong linear relationship exists between the amount of gliadin (0.01-1.0 mg/mL) and the corresponding ΔC response (total capacitance decrease during a 20 min monitoring period after sample introduction), with an R2 of 0.9843. The detection limit is 0.007 mg/mL (S/N > 5), equivalent to 0.014 mg/mL (14 ppm) of gluten content. Spike recovery tests identified this system is free from interferences in corn and cassava flour matrices. The analytical results of 24 commercial wheat flour samples correlated well with a gliadin ELISA assay (R2 = 0.9754). The proposed label-free and reagentless capacitive aptasensor offers advantages of simplicity, cost-effectiveness, ease of production, and speediness, making it a promising tool for verifying products labeled as gluten-free (gluten content <20 ppm).