Abstract

Herein, graphene oxide nanoribbons (GONRs) were obtained from the oxidative unzipping of multi-walled carbon nanotubes. Covalent coupling reaction of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxy succinimide (NHS) with amine functional groups (-NH2) of the chitosan natural polymer (CH) was used for entrapping GONRs on the activated glassy carbon electrode (GCE/GONRs-CH). The nanocomposite was characterized by high-resolution transmission electron microscopy (HRTEM), and field-emission scanning electron microscopy (FESEM). In addition, the modification steps were monitored using FTIR. The nanocomposite-modified electrode was used for the simultaneous electrochemical determination of four DNA bases; guanine (G), adenine (A), thymine (T) and cytosine (C). The nanocomposite-modified GCE displayed a strong, stable and continuous four oxidation peaks during electrochemistry detection at potentials 0.63, 0.89, 1.13 and 1.27 V for G, A, T and C, respectively. The calibration curves were linear up to 256, 172, 855 and 342 μM with detection limits of 0.002, 0.023, 1.330 and 0.641 μM for G, A, T and C, respectively. The analytical performance of the GCE/GONRs-CH has been used for the determination of G, A, T and C in real samples and obtained a recovery percentage from 91.1%–104.7%. Our preliminary results demonstrated that GCE/GONRs-CH provided a promising platform to detect all four DNA bases for future studies on DNA damage and mutations.

Highlights

  • Deoxyribonucleic acid (DNA) bases are the fundamental building blocks of all life

  • Our results showed that glassy carbon electrode (GCE)/graphene oxide nanoribbons (GONRs)-CH enabled the simultaneous and individual detection of all four DNA bases with a good limit of detection as well as maintaining an acceptable dynamic range

  • Using common ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC)/N-hydroxy succinimide (NHS) amine coupling activation of GCE surfaces, the nanocomposite was successfully attached on the surfaces as displayed by the CV and electrochemical impedance spectroscopy (EIS) studies

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Summary

Introduction

Deoxyribonucleic acid (DNA) bases are the fundamental building blocks of all life. There are four naturally found bases, with two subgroups. Guanine (G) and adenine (A) are in the group of purine bases in which the structure contains an aromatic pyrimidine ring fusing with an imidazole ring [1]. The second subgroup is the pyrimidines which are thymine (T) and cytosine (C), which only contain an aromatic pyrimidine ring within its structure [2]. By varying the sequence of these four bases, proteomic, metabolomic and physiological information can be stored and recalled at any time. In the human genomic sequence, if a mutation or damage occurs within the sequence it can lead to detrimental diseases such as cystic fibrosis, sickle cell anemia and Alzheimer’s disease [3,4,5]

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