▎ 摘　　要

We report the synthesis and characterization of graphene nanoribbons (GNRs) decorated with iron oxide (Fe3O4) nanoparticles to obtain the GNR_Fe3O4 nanocomposite and its use as a DNA sensor. Characterization results confirm the successful synthesis of a nanocomposite based on reduced GNRs and mostly Fe3O4 nanoparticles distributed randomly and homogeneously on the ribbon's surface and whose specific surface area (766 m(2) g(-1)) is higher compared to pure GNRs (588 m(2) g(-1)). These characteristics make this nanocomposite suitable for effective DNA immobilization and hybridization in sensor applications. Taking advantage of the latter, the electrochemical analysis demonstrated that GNR_Fe3O4-based electrodes amplify the electrochemical signal by more than one order of magnitude compared to bare carbon electrodes, and 70% more compared to pristine GNRs-based electrodes. The capability of the GNR_Fe3O4 nanocomposite as a DNA sensor was evaluated in terms of the electrochemical response by monitoring the cathodic peak in DNA immobilization and hybridization through a redox process. The electrochemical current was measured in immobilized single-stranded DNA and double-stranded DNA to be 92 and 49 mu A, respectively, for GNR_Fe3O4-based electrodes; these values are indicative of an effective discrimination between the immobilization and hybridization of DNA. The present work demonstrates the viability of a DNA sensor based on the facile synthesis of GNRs decorated with Fe3O4 nanoparticles. Published under license by AIP Publishing.