Electro-Sensing Analysis for Parkinson's Disease Biomarker on Dual-Electrode Surface: Complemented by Molecular...

This study was designed to improve the sensitivity, specificity, and selectivity of the electrochemical method of detecting Parkinson's disease by identifying alpha-synuclein as a biomarker using gold interdigitated electrodes (AuIDEs with and without surface modified with zinc oxide (ZnO). AuIDE modified with zinc oxide and AuIDE without zinc oxide were characterized using a scanning electron microscope, 3D profilometers, and a high-power microscope. Current-voltage measurements were performed for antigen-antibody interaction and targeted detection using a Keithley 6482 Picoammeter. The linear range was from 1 fM to 1 pM. The limit of detections for AuIDE modified with zinc oxide and AuIDE without zinc oxide were calculated using the signal-to-noise ratio (S/N) = 3 formula. Linear regression analysis of the AuIDE without zinc oxide was R² of 0.9779. The linear regression analysis for AuIDE with zinc oxide was R² = 0.9809. Regression analysis thus yielded a better result in the modified AuIDE. For the determination of selectivity, alpha-synuclein and tau were tested on the surface-modified AuIDE. Tau was used as a control variable. However, only alpha-synuclein produced significant current change, while the control protein yielded no significant changes. Hence, the inclusion of the ZnO layer improved the sensor's performance and the sensor was reproducible and stable after repeated testing.