Automated Sample Preparation and Food Allergen Detection via Injection-Molded Centrifugal Microfluidics

Food allergies pose a serious and increasing public health challenge as many allergens can trigger potential life-threatening reactions in affected individuals. Reliable detection of allergens such as soy proteins is therefore a critical and essential tool to detect cross-contaminations, particularly in food processing and production environments. To enable monitoring directly at these sites, portable biosensing platforms are required to provide rapid point-of-need detection. However, the development of such systems requires the combination of biochemistry, material science, and precision engineering. In this article we present a centrifugal microfluidic platform integrating automated sample preparation, clean-up, and immunological detection in a single-use disposable cartridge. Targeting soybean protein as a model allergen, the system combines optimized immunoassay chemistry with advanced polymer microfabrication. Regioselective antibody coupling strategies were investigated for stable and oriented bead conjugation. N-glycan click chemistry was used to produce monodisperse, highly functional fluorescent microbeads. The microfluidic LabDisk was first manufactured by thermoforming and later transferred to injection molding with integrated optical elements to increase sensitivity. The fully integrated LabDisk detected soy protein at the lowest concentrations tested, namely 1 ppm in extraction buffer and 4 ppm in incurred complex matrices. This work shows the important steps from biochemical concept to scalable manufacturing, paving the way for mass-produced, portable allergen biosensors.