A colorimetric sensor for DNA detection: Combination of synergistic coupling catalysis and significant distinction in the dimensional structure of DNA

Abstract

Herein, the simple and highly sensitive colorimetric sensor for DNA detection was constructed using the close correlation between DNA dimension and peroxidase activity of graphene oxide (GO)/AuNPs nanocomposite. One-dimensional and linear ss-DNA was hybridized into double helix DNA of three-dimensional space conformation, resulting in that catalytic activity of GO/AuNPs for the oxidation of enzyme substrate TMB significantly enhanced. Thus, DNA dimension transformation caused by hybridization is converted into color rendering events of TMB oxidation. The results show that the dimensional transformation of DNA can efficiently regulate the peroxidase activity of GO/AuNPs. Together with the effective amplifying for the color reaction of TMB by GO/AuNPs’ synergistic coupling catalysis at the nanometer interface, the colorimetric sensor is highly sensitive to DNA detection. The detection limit is calculated to be 8.8 × 10−12 M, which is about 1 ~ 2 orders of magnitude lower than that of other nanozyme colorimetric analysis. Besides, this analysis only requires one-step hybridization reaction, and the whole analysis is carried out in the homogeneous system of liquid phase, which is extremely easy to operate and conducive to the automatic sensing design. The detected results for serum samples declare that this sensor has great potential in the application of real life systems.