A colorimetric sensor for the detection of hydrogen peroxide using DNA-modified gold nanoparticles

Reactive oxygen species (ROS) are byproducts of biological reactions of energy generation, and depending on their concentration, ROS can be beneficial or harmful to cells and tissues. However, excessive ROS is hazardous. In this study, we used DNA-modified gold nanoparticles to develop colorimetric detection for hydrogen peroxide (H2O2). The assay has two steps. In the first step, ferrous ions are added into samples to react with hydrogen peroxide producing hydroxyl radicals (·OH) based on the Fenton reaction. In the second step, DNA-modified gold nanoparticles and sodium chloride are added. When hydrogen peroxide is present the color of the solution changes from red to purple because the hydroxyl radicals break the phosphodiester bond in the DNA and decrease the quantity of DNA on the surface of gold nanoparticles causing gold nanoparticle aggregation. All the operating steps could be completed in 15 min and the limit of detection (LOD) was 1 µM. This rapid colorimetric assay has potential for application in detection of other ROS.81