Low temperature growth of ZnO nanotubes for fluorescence quenching detection of DNA.

In this work, large-scale and single-crystalline ZnO nanotubes were fabricated by a simple technique from an aqueous solution at a low temperature of 65 °C. According to detailed morphology, structural and compositional analyses showed that the ZnO nanotubes [diameter ~200 nm (wall thickness ~50 nm); length ~1 µm] have single-crystallite with wurtzite structure. As-prepared ZnO nanotubes showed an effective fluorescence quenching for the detection of calf thymus DNA. In particular, increasing DNA concentrations (5-50 µM) into the fixed concentration of ZnO nanotubes (50 µM) progressively quenched the intrinsic fluorescence of nanotubes, which showed that the nanotubes fluorescence was efficiently quenched upon binding to DNA. At the highest ZnO-DNA molar ratios of 1:1.8, around 50.1 % of fluorescence quenching of DNA was observed. Significance of this study provides simple, cost-effective, and low temperature synthesis of ZnO nanotubes revealed better fluorescence property toward a platform of DNA sensor. ZnO nanotubes with diameter of ~200 nm (wall thickness ~50 nm) and length of about 1 µm prepared at low temperature (65 °C) showed fluorescence was efficiently quenched upon binding to DNA. In particular, around 50.1 % of DNA fluorescence quenching at the highest ZnO-DNA molar ratios of 1:1.8 was observed.