Application of diazo-thiourea and gold nano-particles in the design of a highly sensitive and selective DNA biosensor

An effective procedure for constructing a DNA biosensor is developed based on covalent immobilization of NH2 labeled, single strand DNA (NH2-ssDNA) onto a self-assembled diazo-thiourea and gold nano-particles modified Au electrode (diazo-thiourea/GNM/Au). Gold nano-particles expand the electrode surface area and increase the amount of immobilized thiourea and single stranded DNA (ssDNA) onto the electrode surface. Diazo-thiourea film provides a surface with high conductibility for electron transfer and a bed for the covalent coupling of NH2-ssDNA onto the electrode surface. The immobilization and hybridization of the probe DNA on the modified electrode is studied by differential pulse voltammetry (DPV) using methylene blue (MB) as a well-known electrochemical hybridization indicator. The linear range for the determination of complementary target ssDNA is from 9.5(±0.1) × 10−13 mol/L to 1.2(±0.2) × 10−9 mol/L with a detection limit of 1.2(±0.1) × 10−13 mol/L.

Graphical abstractAn effective procedure for fabrication of DNA biosensor was developed based on covalent immobilization of NH2 labeled single strand DNA onto a self-assembled diazo-thiourea gold nano-particle modified Au electrode.Figure optionsDownload full-size imageDownload as PowerPoint slide