DNA analysis based on the electrocatalytic amplification of gold nanoparticles

Abstract

The detection of deoxyribonucleic acid (DNA) has a very important significance in life sciences. The paper demonstrates a novel and effective electrochemical detection method of observing single nanoparticle (NP) collision events as signal label to amplify electrocatalytic activity for hydrazine electrooxidation in a sandwich-type DNA sensor. The Au NP was characterized by UV–vis spectrophotometer and transmission electron microscope (TEM). Hydrazine oxidation on DNA-modified Au NP was compared with that on Au NP by cycle voltammetry (CV). Via NaBH4 treatment the enhancement of electrocatalytic activity of DNA-modified Au NPs was proposed and applied to the sandwich-type DNA sensor. It is discussed by cyclic voltammetry, linear sweep voltammetry (LSV), and chronoamperometry (CA). The result showed that the Au NP of 3–4 nm diameters had large specific surface area and less prone to agglomeration with good electrocatalytic activity. Cyclic voltammetry displayed that the current of electrode increased 1.103–1.889 × 10−8 A after NaBH4 treatment in the different concentrations of target DNA. Target DNA could be detected at concentration ranging from 1 pM to 100 nM and the detection limit was 1 pM. It can be applied to the development of even more sensitive biosensors.