A sensitive and disposable indium tin oxide based electrochemical immunosensor for label-free detection of MAGE-1.

MAGE-1 (MAGE, for melanoma antigen), was identified by virtue of its processing and cell surface expression as a tumor-specific peptide bound to major histocompatibility complexes which was reactive with autolytic T cells. 3-Glycidoxypropyltrimethoxysilane (3-GOPS) is frequently employed for the preparation of dense heterometal hybrid polymers which are used, e.g., for hard coatings of organic polymers and contact lens materials in the optical industry. In this study, we have improved a new immunological biosensor with indium tin oxide (ITO). Then, Anti-MAGE-1 antibody was covalently immobilized with 3-GOPS which formed a self-assembled monolayers (SAMs) on modified ITO electrodes. Analytical characteristics such as square wave voltammetry, linear determination range, repeatability, reproducibility and regeneration of biosensors are determined. All characterization steps are monitored by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV). The developed biosensor has wide determination range (0.5fg-15fg/mL). To investigate long shelf life of the fabricated biosensor, the immunosensors were stored at 4°C for periods ten weeks. Futhermore, binding kinetics of MAGE1 to antiMAGE-1 is monitored by single frequency technique in real time. Additionally, Kramer's-Kronig transform was used to understand whether the impedance spectra of biosensor system are affected from the variation that occurred because of external factor. Morphological characteristics of constructed biosensor were observed by scanning electron microscopy. Real human serum samples were also analyzed by the proposed biosensor, successfully. A commercial ELISA kit was also used as a reference method to validate the results obtained by the biosensor. Finally, this biosensor was tried in real blood sample and that showed it could be utilized in clinical applications. This biosensor can be preferred due to it has a wide linear range and it can be prepared easily.