Electrocatalytic Oxidation of DNA-Wrapped Carbon Nanotubes

Abstract

The electrical properties of single-walled carbon nanotubes (CNT) are of intense interest due to applications in nanoelectronics. Cyclic voltammetry and chronoamperometry have been used to explore the Ru(bpy)₃²⁺ electrocatalytic oxidation of DNA-solubilized carbon nanotubes. Dramatic current enhancements are observed with the addition of a CNT wrapped in an oligonucleotide sequence containing no oxidizable guanines. The current enhancement observed is solely due to the oxidation of the CNT by electrogenerated Ru(III) and subsequent recycling of the metal complex redox reaction. The chronoamperometric (CA) response is biphasic, and rate constants derived from the CA response were used to develop digital simulations of the cyclic voltammograms collected at the same CNT concentrations. Ten successive C‘ reactions were required to account for all of the observed signal. The oxidation of the CNT is a multielectron process, and this effect arises from the multiple electron donor sites in the carbon nanotube as well as the over oxidation of each site.