Etching silver nanoparticles using DNA

Abstract

While DNA has been widely used for directing the growth and assembly of nanomaterials, the reverse reaction, etching nanoparticles using DNA, has yet to be demonstrated. We herein communicate that poly-cytosine (poly-C) DNA can efficiently etch silver nanoparticles (AgNPs) followed by Ostwald ripening at higher DNA concentrations. The etching process was precisely controlled by varying the length, sequence, and concentration of DNA, and the number of consecutive cytosines is particularly important for the efficacy of etching. In addition to spherical AgNPs, etching also occurred for silver nanoplates displaying interesting color changes. Compared to other chemical etching agents such as H₂O₂ and ferricyanide, DNA is highly biocompatible, allowing biological applications. Poly-C etching enhanced the cytotoxicity of AgNPs against cancer cells, and Gram-positive and Gram-negative bacterial cells. This study will stimulate many related studies in DNA nanotechnology, bioanalytical sensors and nanomedicine.