Development of a Microfluidic Paper-Based Immunoassay for Rapid Detection of Allergic Protein in Foods

Food allergy affects up to 10% of the population, causing moderate to severe systemic symptoms and even death. Detecting allergens in food is the most critical and effective measure to reduce food allergy incidents, but the most commonly used kits, lateral flow immunoassay (LFI), are still relatively high in cost for the food industry. Microfluidic paper-based analytical devices (μPADs) demonstrate the potential to address this challenge by substituting the multiple parts/materials in LFI with solely (cellulose) paper as the platform. This study reports the development of a single-piece lateral flow μPAD and demonstrates its capability of detecting allergic protein in various food samples within a 15 min including sample preparation. A confined reagent deposition on the testing zone of the patterned paper was achieved by blade cutting. Surface modification of the cellulose was optimized to enable the complete release of recognizing conjugates and elimination of background noise. The geometry of patterns was optimized to meet the liquid sample's requirement in flow rate. This LFI-format μPAD can detect as low as 1 ppm ovalbumin in standard solution, 0.01% (w/w) egg white protein in spiked cake mix, and the egg content in other commercial food products. Much simpler fabrication procedures and a lower material cost are required by the μPAD than that by conventional LFIs. With the potential to scale up, this study provides an alternative food monitoring option to many sectors throughout the agri-food chain and contributes to improving food safety and public health.