DNA biosensor based on surface modification of ITO by physical vapor deposition of gold and carbon quantum dots modified with neutral red as an electrochemical redox probe

Abstract

Here, we report on an effective modified DNA biosensor. First, the surface of an indium tin oxide (ITO) is modified with gold via physical vapor deposition technique. Second, we also report on the synthesis of carbon dots, which are modified with neutral red as an electrochemical redox probe. The different steps of modifications are monitored with atomic force microscope, UV–Vis spectroscopy, fluorescence spectroscopy FT-IR spectroscopy, dynamic light scattering and as well as different electrochemical techniques. The biosensor is applied for determination of salmonella DNA sequence at ultra-low concentrations with linear range of 20–240 fM and 10 fM limit of detection. The ability of detection of the target of biosensor is evaluated in spiked samples.