Allergen‐Functionalized Microfluidic Immunoadsorption Platform for Selective Depletion of Peanut‐Specific Antibodies From Whole Blood

ABSTRACT Peanut allergy can lead to severe and life‐threatening reactions, yet management still relies primarily on strict peanut avoidance. Because IgE antibodies play a critical role in driving allergic responses, several therapeutic strategies target the IgE pathway. However, these approaches often require biologics and can be limited by cost, dosing constraints, or systemic side effects. Here, we present a microfluidic immunoadsorption platform functionalized with a layer‐by‐layer (LbL) assembly of poly(diallyldimethylammonium chloride) (PDDA) and peanut allergens nanofilms to selectively capture peanut‐specific antibodies directly from the whole blood of peanut allergy mouse. The LbL coating formed a uniform surface in microfluidic channels as confirmed by fluorescence microscopy, SEM, and QCM‐D assessments. Using serum from peanut‐sensitized mice, the peanut protein extract (PE) coated device demonstrated efficient depletion of anti‐PE IgG. When operated with unprocessed whole blood, the device achieved measurable removal of PE‐specific antibodies in continuous flow conditions without significant hemolysis, altering red blood cell count, mast cell activation, or oxidative stress. These results demonstrate that PE functionalized LbL microfluidic immunoadsorption enables selective antibody depletion using minimal blood volumes and without preprocessing, offering a low shear and biocompatible alternative to conventional extracorporeal systems.