IgY - electrochemical immunosensor based on nanoelectrodes ensemble

Abstract It has been recently demonstrated that chicken egg-yolk immunoglobulin Y (IgY) has many immunological properties not only on avian, but also on mammalians, such as human [1]. Since it is easy to insulate (directly from egg yolk – where it is present at a concentration of 10 mg/mL), recently scientists proposed new immunotherapies based on the addiction of IgY to medicine or food both for animals and humans [1]. In addition, eggs are very common ingredients in all diets, so it is important to understand if it is possible to obtain such immunological properties from every day foods, or if IgY degrades during cooking procedures and temperature changes. For this reason, we developed an electrochemical immunosensors based on Au-nanoelectrodes ensemble (NEE) as transducer, able to identify IgY in different matrices. NEEs are prepared via template electroless deposition of gold in a polycarbonate (PC) membrane. Polycarbonate is affine to proteins and antibodies and, for these reason NEEs are very suitable to be used both as electrodes and as protein-receiver material [2]. IgY, the biological molecular recognition element, is immobilized directly on the PC surface of the electrode. It is recognized by the secondary antibody anti-IgY labelled with HRP, an electroactive enzyme that reacts with his substrate (H2O2) and a redox mediator (methylene blue), originating the electrocatalytic cycle. Only the reduction of the oxidated form of methylene blue is an electrochemical reaction, so it is possible to observe an electrocatalytic peak. The proposed immunosensor was tested on different samples, starting from standard IgY, then on analytes collected from yolk or egg-white, and following from more complex food samples containing egg yolk or full cooked eggs. In this communication, the obtained results are presented and discussed.