Characterization of Carboxylated-SWCNT Based Potentiometric DNA Sensors by Electrochemical Technique and Comparison with Potentiometric Performance

Abstract

Aptasensors for detection of thrombin were produced by covalently linking aptamer (ssDNA) to cSWCNT. Those biosensors were fully characterized by cyclic voltammetry to evaluate the electrode surface charge/ligand density. We performed the CV studies of electrostatically bound [Ru(NH3 )6]3+ redox markers on aptamer surfaces and calcu- lated aptamer surface charge density from the CV data. Potentiometric detection of thrombin allows then the correla- tion with the CV results. The electrode surfaces containing higher amount of aptamers exhibited better performance in potentiometric measurements. These investigations will introduce the pathway to build reusable and regenarable aptasensors including a simple, accurate and precise estimation of aptemer surface charge density to characterize the surface and hence to ensure the quality of apatsensors.