WITHDRAWN: Au nanoparticle-modified SiO2 thin film for DNA immobilization and hybridization

Abstract

Abstract The potential of using gold nanoparticles (GNPs) for DNA biosensors application has been fabricated a power techniques utilized. GNPs were examined by utilizing the UV–Vis, transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). An electrochemical DNA biosensor was successfully fabricated by depositing (3-aminopropyl) tri-ethoxysilane (APTES) and gold nanoparticles on thermally oxidized SiO 2 thin films. DNA was held immobilized onto the GNPs surface by different periods of 0.5, 1, 2, and 4 h, respectively, and hybridization with complementary DNA was performed. The results showed that DNA immobilization and hybridization were conducted by measuring the differences in capacitance values within the frequency range of 1 to 10 6 Hz. The capacitance values for DNA immobilization that have been measured are 191, 72.4, 69.3, and 67.3 µF from 30 min to 4 h Meanwhile, the capacitance values for DNA hybridization were 60, 59.3, 58.4, and 46.2 µF. The capacitance value of bare SiO 2 thin film was 0.427 µF, which was set as a base line for a reference in DNA detection. Immobilization and hybridization were performed using potassium hexacyanoferrate with cyclic voltammetry (CV) software for measuring the sensitivity of the fabricated electrode. The differences in capacitance value between DNA immobilization and hybridization revealed that the modified SiO 2 thin films using APTES and GNPs have successfully developed for DNA detection.