Nanopore immunosensor for peanut protein Ara h1

A nanopore immunosensor is demonstrated for peanut protein Ara h1, a common food allergen. This biosensor is constructed by immobilizing the antibody to peanut protein Ara h1 within Au-coated pores of commercial nanoporous polycarbonate membranes. Peanut protein Ara h1 is detected as the change in the pore conductivity as the pores are partially obscured by antigen binding. Control experiments with the antibody to cockroach protein Bla g1 demonstrate that the observed effects do not arise from non-specific adsorption. Binding of peanut protein is studied as a function of the pore diameter (15, 30 and 50 nm), and as a function of the concentration of peanut protein. The results show the greatest sensitivity for membranes with the smallest pore diameter, and exhibit mass transfer effects for membranes with larger pore diameters. Approximate calculations of diffusion times for transport of peanut protein Ara h1 through these nanoporous membranes suggest that mass transport effects should not be observed. This discrepancy between experimental observations of mass transfer effects and model predictions suggest that diffusion of peanut protein Ara h1 is anomalously slow in this system.