Synthesis and characterization of Ag-Ni nanorings based on plasmid DNA templates

Ag-Ni nanorings were synthesized by using toroidal topology Plasmid DNA with 7500 base pairs as templates. The photoirradiation method was employed to reduce metallic cations and deposited on the Plasmid DNA forming nanorings. The Plasmid DNA was separated from Bacillus hosts by using molecular biology methods. The morphology, composition, and structure of the nanorings were characterized by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS) and selected-area electron diffraction (SAED). The UV-vis spectrum was applied to study the different stages of the synthesis processes. It was found that the Ag-Ni was successfully deposited on the surface of the Plasmid DNA and formed the nanorings. The nanorings exhibit monodispersity and with an outer diameter of ∼ 50 nm and an inner diameter of ∼ 30 nm. It was suggested that this approach has promising application for the synthesis of other metal or alloy nanorings.