Development of impedimetric immunosensor for the detection of amyloid beta (1-40) on maβa/ortho-polyphenylenediamine modified platinum micro disk electrode

• Published in: International Journal of Electrochemical Science
• Main Author: Norazreen Z.; Zainiharyati M.Z.
• Format: Article
• Language: English
• Published: Electrochemical Science Group 2016
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958211944&doi=10.1016%2fs1452-3981%2823%2915890-1&partnerID=40&md5=075ef7406bb4d86941443937f4725391

The development of an electrochemical detection of amyloid beta (Aβ) (1-40) peptides as a bio marker of Alzheimer's disease (AD) was carried out on a Pt disk microelectrode. The electrode was modified with poly-ortho- Phenylenediamine (PPD) and mouse monoclonal beta amyloid antibody (mAβA) was immobilized to form Pt/PPD/mAβA immunosensor. The measurements were done in Phosphate Buffer Solution (PBS) by applying Electrochemical Impedance Spectroscopy (EIS) technique. The detection is evaluated by the changes in the Nyquist spectra and values of charge transfer resistance (Rct) that were extracted from a modified Randles equivalent circuit. A semi-circle Nyquist plot was observed in the presence of Aβ (1-40) whereas a linear spectra were exhibited in the absence of Aβ (1-40). In addition, as the concentrations of Aβ (1-40) solution increased, the diameter of Nyquist plots was also increased. Surface morphology of Aβ (1-40) adsorbed on microelectrode was observed using Field-emission Scanning Electron Microscope (FESEM) and Optical Microscopic. Based on these findings, a promising in vivo immunosensor for Aβ (1-40) detection that can be used as an alternative in monitoring inhibitors of Aβ (1-40) aggregation research.