Electrochemical and optical biosensing platforms for the immunorecognition of hazelnut Cor a 14 allergen

Two immunosensors were advanced to target hazelnut Cor a 14 based on electrochemical and optical transduction. Both approaches were developed with two types of custom-made antibodies, namely anti-Cor a 14 IgG (rabbit) and anti-Cor a 14 IgY (hen's egg) targeting the Cor a 14 allergen. Antibody immobilisation was performed via EDC/NHS onto disposable screen-printed electrodes. The detection limit (LOD) of the electrochemical immunoassay for Cor a 14 was 5-times lower than the optical, being down to 0.05 fg mL^-1 with a dynamic range of 0.1 fg mL^-1 to 0.01 ng mL^-1. Antibody selectivity was verified against non-target 2S albumins (potential cross-reactive plant species). Anti-Cor a 14 IgY exhibited the best specificity, presenting minor cross-reactivity with peanut/walnut. Preliminary results of the application of anti-Cor a 14 IgY electrochemical immunosensor to incurred foods established a LOD of 1 mg kg^-1 of hazelnut in wheat (0.16 mg kg^-1 hazelnut protein).