A comparative study of electrochemical performances of carbon nanomaterial-modified electrodes for DNA detection. Nanotubes or graphene?

A comparative study about the electrochemical response of glassy carbon electrode modified with four different carbon nanomaterial (CNM) against dsDNA is reported. The CNM used were oxidized and nonoxidized multiwalled carbon nanotubes (MWNT-OX and MWNT, respectively), graphene oxide (GO) and chemically reduced graphene oxide (RGO) and dispersed in 3:1 chitosan/water mixture. The electrodes were characterized by cyclic voltammetry, scanning electrochemical microscopy, and contact angle measurements. The results showed that the type and degree of oxidation have a strong effect on the electroactivity of the modified electrode. GCE/RGO clearly exhibited the most electroactive surface among the CNMs, demonstrating that the graphitic structure is highly important. A more sensitive electrochemical response against dsDNA was obtained when GCE/RGO electrode was used. Therefore, RGO is the CNM recommended for further consideration in the development of DNA biosensors.