Abstract: This study developed a novel microfluidic electrochemical immunosensor based on microfluidic technology and electrochemical immunosensing for the detection of food allergy biomarkers. The sensor utilized screen-printed carbon electrodes (SPCEs) modified with electrodeposited gold nanoparticles (AuNPs) to construct gold nanoelectrodes and was integrated with microfluidic chips to achieve automated sample processing and detection. An 11-mercaptoundecanoic acid (11-MUA) self-assembled monolayer (SAM) was used as the immobilization substrate to construct a streptavidin-biotinylated antibody system. Using the impedance response variation of the redox mediator K3[Fe(CN)6], the chemical changes within the microchannels were converted into electrode impedance signals by an electrochemical workstation, ultimately enabling quantitative detection of the allergen biomarker OX40L based on the impedance values. The sensor exhibited a linear range from 10 to 7 500 pg/mL, a low detection limit (LOD) of 10 pg/mL, and coefficient of variation < 10%, and allowed successful electrode regeneration. Furthermore, the integration of the sensor with a gut-on-a-chip platform achieved real-time dynamic monitoring of cytokines stimulated by four allergens (e.g., ovalbumin, gliadin), and interfacing it with external devices such as electrochemical workstations allowed continuous monitoring of ovalbumin for up to 80 hours. In summary, this integrated system offers the advantages of miniaturization, high sensitivity, and automation, providing a novel technical platform for allergy mechanism research and food safety detection.

Key words: microfluidic chip; electrochemical immunosensor; gold nanoelectrode; food allergy biomarkers