DNA Electrochemical Biosensor Based on Chitosan and Gold Nanoparticles Using Methylene Blue as Electrochemical Indicator

Abstract

In this paper, a novel DNA electrochemical biosensor based on layer-by-layer self-assembled technology was reported. Gold nanoparticles were firstly immobilized on chitosan modified gold electrode by large amino of chitosan because of strong electrostatic adsorption effect between amino and gold atom, and thoil group modified DNA (SH-ssDNA) probe sequence was then self-assembled onto the electrode. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were applied to investigate the electrochemical behavior of different modified electrodes with methylene blue as hybrid indicator. The results in optimization experiment condition show that: The peak current difference value pre and post hybridization was linearly related to the logatithmic value of the target DNA concentration ranging from 10-8~10-5mol/L.A detection limit of 3.55×10-9mol/L can be estimated.