Milk Allergen Detection: Sensitive Label-Free Voltammetric Immunosensor Based on Electropolymerization

We present in this work, first time in literature, a voltammetric label-free biosensor for detection of alpha lactalbumin (alpha-LB) in meal samples. Food allergy concern necessitates strict regulations in food labelling and innovative monitoring strategies for prevention of sepsis-related death. As major food allergens, dietary samples often contain whey proteins, including alpha-LB as one of the key allergenic. Available detection methods for alpha-LB are based on successive labelling steps and hence have long assay times with limited sensitivity. The new detection method presented here is based on capturing of alpha-LB via entrapped alpha-LB antibody (alpha-LB-Ab) through electropolymerization of polypyrrole (PPy) and then measuring the conductivity decrease by differential pulse voltammetry (DPV). This new label-free voltammetric biosensor for alpha-LB exhibits the best limit of detection (0.19 fg/mL) published so far in literature, with high selectivity and capability to quantify alpha-LB in real milk samples too.