Admittance Biosensor Based on Aptamer and Nano Composite Film for Determination of Thrombin using Coulometric Admittance Voltammetry

This work describes a novel thrombin admittance biosensor based on self-assembled anti-thrombin-aptamer. The biosensor was constructed by modification of glassy carbon electrode by using of MWCNT- 1-butyl-3-methylimidazolium hexafluorophosphate, electro-deposition of gold nanoparticles and finally loading DNA aptamer on the electrode surface. The electrochemical response of thrombin (in form of coulometric admittance) was obtained by coulometric FFT admittance voltammetry (CFFTAV). The analyte signal was established on the decrease of the admittance related to the redox couple of probe (Fe(CN)6]3−/4−). The influences of important parameters in the determination process were investigated, and optimized. The change in the analyte response was proportional to the concentrations in range of 0.03 to 18 nM, with a detection limit of 8×10-12 M. Moreover, the proposed biosensor exhibited high sensitivity and long-term stability. The biosensor was successfully used to the determination of thrombin content in the biological samples