GOLD CD-SENSOR PLATFORM FOR DNA APTAMER ASSEMBLING TOWARDSHUMAN THROMBIN RECOGNITION

In this work, we report an aptamer biosensing array for thrombin detection by measuring the electrochemical impedance spectroscopy (EIS) upon aptamer-protein formation at the surface of gold CDtrodes (GCDTs) in the presence of redox couple [Fe(CN)6]3-/4- [2]. The biosensor was constructed by self-assembling a thiol-modified thrombin binding aptamer (TBA) onto the GCDT surface followed by the protein addition in a wide range of concentrations ranging from 20 nM to 1 microM. Achieved results reveal that the GCDTs present good versatility and suitable reproducibility for thrombin recognition with a limit of detection (LOD) of 5 nM. Non-specific interaction with similar molecular compounds like bovine serum albumin (BSA) demonstrates an appropriate and specifically target sensor response thanks to the aptamer incorporation as transducer elements. In order to verify the practical application of GCDT aptasensor in complex biological fluids, we have detected thrombin in spiked diluted blood plasma samples. Additionally, individual steps of biosensor assembling were monitored by Scanning electron microscopy (SEM). GCDT response was also satisfactory compared with commercial gold screen printed electrodes (GSPE).