Porous Au/AAO: A simple and feasible SERS substrate for dynamic monitoring and mechanism analysis of DNA oxidation

Abstract

Herein, a simple strategy was proposed to acquire an orderly and controllable periodic structure. Firstly, the optimal parameters of porous anodic aluminum oxide (AAO) were screened out by FDTD solutions. Combined with magnetron sputtering of gold nano-film, the Au/AAO SERS substrate was thus fabricated. The enhancement factor (EF) was calculated to be 4.87 × 106, and SERS spectra with good reproducibility were also acquired. The oxidization process of plasmid DNA was thus monitored under the conditions of low detection power and short integration time. Fenton's reagent was used as oxidizing reagent, and Na2SO4 was applied for the internal standard in SERS analysis. The changes of I657/I998, I723/I998, I1587/I998, I1648/I998 were studied over time. DNA oxidation product 8-OHdG was also detected in this process. Then the relationship between the relative peak intensity ratios and the base structure change in DNA was established. The conclusions of SERS spectral analysis were verified by agarosegelelectrophoresis, DNA oxidative damage gel detection and colorimetric detection of 8-OHdG. The mechanism analysis of DNA oxidation process was thus studied. The simple and feasible detection strategy proposed could extend the application of SERS technology in the process monitoring of photosensitive or other unstable biological samples.