Competitive electrochemical immunosensor for amyloid-beta 1-42 detection based on gold nanostructurated Screen-Printed Carbon Electrodes

Alzheimer's disease is the most common form of dementia, characterized by the progressive accumulation of plaques with amyloid-beta peptide of 42 amino acids as one of the primary constituents. A disposable electrochemical immunosensor for the detection of amyloid-beta 1-42 is developed. Screen-Printed Carbon Electrodes nanostructured with gold nanoparticles generated “in situ” are used as the transducer surface. The immunosensing strategy consists in a competitive immunoassay: biotin-amyloid-beta 1-42 immobilized on the electrode surface and the analyte (amyloid-beta 1-42) compete for the anti-amyloid-beta 1-42 antibody. The electrochemical detection is carried out using an alkaline phosphatase labeled anti-rabbit IgG antibody. The analytical signal is based on the anodic stripping of enzymatically generated silver by cyclic voltammetry. The immunosensor achieved shows a low limit of detection (0.1 ng/mL) and a wide linear range (0.5-500 ng/mL).