Impedimetric immunosensors for the detection of Cry1Ab proteinfrom genetically modified maize seeds

Regardless the controversies surrounding genetically modified organisms (GMO), their cultivation isconstantly increasing and in according to the EU legislation, labeling is mandatory for products con-taining EU-authorized-GMO higher than 0.9%. Thereby, new analytical strategies for rapid and effectivedetection of GMO on foodstuffs are required. In this work, an electrochemical immunosensor foreffective determination of Cry1Ab protein from MON810 transgenic maize (EU-authorized-GMO) isdescribed. The immunosensor was developed onto indium tin oxide (ITO) electrodes modified by3-aminopropyltrimethoxysilane (APTES) monolayer to covalently immobilize Anti-Cry1Ab polyclonalantibodies. The protein interaction with the polyclonal antibody (PAb) recognition platform was directlymonitored and measured by cyclic voltammetry and electrochemical impedance spectroscopy usingcommercially Cry1Ab protein. After the analytical features optimization a linear response from 1 to10 ng mL−1, a limit of detection (LOD) of 0.37 ng mL−1and a limit of quantification (LOQ) of 1.23 ng mL−1– which provided accurate results (RSD < 7.5%) – were achieved. The immunosensor allowed a simple andfast detection of Cry1Ab protein extracted from maize seeds with different GM maize mass percentages(0%, 0.5%, 1%, 2.5% and 5%). To crosscheck the detection of Cry1Ab protein, an enzyme-linked immunosor-bent assay (ELISA) was used. The results indicate that the immunosensor is suitable for the transgenicprotein Cry1Ab detection in GM maize representing a successfully tool to verify the compliance of theEU regulations.