A novel highly sensitive soy aptasensor for antigen β-conglycinin determination

β-Conglycinin, composed of three subunits (α', α and β), is the main allergen of soy protein which can cause severe allergic reactions, such as diarrhea, decreased growth performance and even death. Among them, the β subunit is more stable and difficult to remove, being one of the main nutritional inhibitors, which can be used to evaluate the concentration of β-conglycinin. However, there is no effective, accurate method for its β subunit rapid detection. Herein, we have successfully selected a high affinity β subunit aptamer (K_d = 6.9 nM) and developed a highly sensitive aptasensor. The aptasensor displayed high specificity and the β subunit at a concentration of 70-350 nM could be detected with a detection limit of 4.48 nM (3S/N). In addition, the recoveries of β subunit were more than 90%, demonstrating its practical properties for complicated conditions such as food quality control and disease diagnosis, without requiring expensive and sophisticated equipment.