Reduced graphene oxide nanoribbon immobilized gold nanoparticle based electrochemical DNA biosensor for the detection of <i>Mycobacterium tuberculosis</i>

Abstract

Tuberculosis is one of the most dreadful diseases caused by Mycobacterium tuberculosis with more than 9 million individuals suffering from it in 2014. Traditional methods of detection are not efficient enough for its quick and reliable detection; therefore, it is imperative to develop methods of its detection in the early stages. Consequently, we report a highly sensitive and selective biosensor for detection of Mycobacterium tuberculosis. In this work, gold nanoparticles (AuNPs, dia. ∼6 nm, 1.81 wt% loading) are immobilized over reduced graphene oxide nanoribbons (RGONRs). An ssDNA/Au/RGONR electrode is prepared by immobilizing Au nanoparticles followed by covalent modification of Au nanoparticles with 5'SH-ssDNA. As per the best knowledge of the authors, the target DNA of Mycobacterium tuberculosis is detected using a ssDNA/Au/RGONR bioelectrode by cyclic voltammetry and chronoamperometric methods for the first time. With high detection efficiency (0.1 fM), the ssDNA/Au/RGONR bioelectrode exhibited better signal amplification and electrochemical response as compared to bare Au and RGONR electrodes. Additionally, the ssDNA/Au/RGONR bioelectrode displayed good linear response to different concentrations of target M. tuberculosis DNA. The ssDNA/Au/RGONR has shown excellent specificity (92%) to Mycobacterium tuberculosis target DNA as compared with non-complementary DNA. The Au/RGONR matrix has the potential to be used as an immobilization platform for single-stranded probe DNAs of different diseases other than tuberculosis reported here.