Azo dyes are among the most used by the Brazilian textile industry, representing around 20-40% of the dyes used for dying cotton, rayon, silk, nylon, wool and leather. The problem is that several investigations using microorganisms and mammalian cells have indicated that many azo dyes have genotoxic activity even at low concentrations. In this project, the development of an impedimetric immunosensor for detection of Red 1 azo dye at low levels of concentration is proposed. In this case, monoclonal antibody anti- Red 1 will be immobilized on the working electrode through protein A to provide the interaction of Fab portion with antigen present in solution. The protein A from Staphylococcus aureus will be directly fixed on the gold electrode surface modified with cystamine or through glutaraldehyde at cystamine. The optimization of experimental parameters (reagents concentrations for previous electrode modification, antibody immobilization and incubations time) for immunosensor construction will carry out by factorial design employing electrochemical impedance measurements (EIS). The device will be characterized by DRIFTS and cyclic voltammetry and then, the affinity reaction between the immobilized antibody and antigen present in solution will be monitored by EIS. This project takes part of Thematic Project entitled "Evaluation of occurrence, toxicity/genotoxicity and process for dye degradation in effluents and superficial waters", so the impedimetric immunosensor will be applied to determine the dye concentration in water samples to be investigated or investigated in others sub-projects of Thematic.
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