A sensitive DNA biosensor fabricated from gold nanoparticles and graphene oxide on a glassy carbon electrode

A sensitive electrochemical DNA biosensor was developed for Helicobacter pylori (H. pylori) detection using differential pulse voltammetry. Single-stranded DNA probe was immobilized on a graphene oxide/gold nanoparticles modified glassy carbon electrode (GO/AuNPs/GCE). A hybridization reaction was conducted with the target DNA and the immobilized DNA on the electrode surface. Oracet blue (OB) was selected for the first time as a redox indicator for amplifying the electrochemical signal of DNA. Enhanced sensitivity was achieved through combining the excellent electric conductivity of GO/AuNPs and the electroactivity of the OB. The DNA biosensor displayed excellent performance to demonstrate the differences between the voltammetric signals of the OB obtained from different hybridization samples (non-complementary, mismatch and complementary DNAs). The proposed biosensor has a linear range of 60.0–600.0pM and a detection limit of 27.0pM for detection of H. pylori. In addition, the biosensor have responded very well in the simulated real sample evaluations, signifying its potential to be used in future clinical detection of the H. pylori bacteria. •Oracet blue as a new electroactive label use in this work.•This DNA biosensor has a good selectivity in presents of single-base mismatch, non-complementary and complementary DNA strands.•The detection limit of this DNA biosensor was 27.0pM.