Direct Electrochemical DNA Sensor based on a new redox oligomer modified with ferrocene and carboxylic acid: Application to the detection of Mycobacterium tuberculosis mutant strain

• Published in: Analytica chimica acta Vol. 994; pp. 10 - 18
• Main Authors: Bizid, Salma, Blili, Saber, Mlika, Rym, Haj Said, Ayoub, Korri-Youssoufi, Hafsa
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 22.11.2017; Elsevier BV
• Subjects: Acetonitrile; Biomolecules; Biosensors; Carboxylic acids; Chemical synthesis; Deoxyribonucleic acid; DNA; DNA biosensor; Electrochemical analysis; Electrochemical impedance spectroscopy; Electrochemistry; Electrodes; Electron transfer; Fourier transforms; Functional groups; Gold; Hepatitis; Hepatitis C; Infrared spectroscopy; Mycobacterium tuberculosis; Poly(p-phenylene); Redox oligomer; Rifampin; Spectrometry; Spectroscopy; Studies; Tuberculosis; Voltammetry; X ray photoelectron spectroscopy; Electrochemistry; Redox oligomer; DNA biosensor; Poly(p-phenylene)
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2017.09.022

A new redox oligomer “oligo-methoxy-phenyl-acetonitrile” (Fc-acid-OMPA) modified with ferrocene groups and carboxylic acids as functional groups in side chains, has been synthesized. The redox indicator has been used for monitoring the electrochemical behavior. The functional groups give the flexibility for direct covalent attachment of biomolecules. The electrochemical properties of the redox oligomer film deposited on gold electrodes have been studied by cyclic voltammetry (CV), which showed a rate of electron transfer of 6.43 s−1. The oligomer has been studied as a transducer for electrochemical DNA sensing and for this purpose the acid functional group of Fc-acid-OMPA was attached with the DNA probe of hepatitis C bearing amino group in 5′ position through amid link. The efficiency of DNA attachment on the oligomer film has been analyzed by X-Ray Photoelectron Spectrometry (XPS) and FT-IR spectroscopy. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) have been used to analyze the biosensor construction and DNA detection. A wide linear range of detection from 1 fM to 100 pM have been demonstrated with a limit of detection (LOD) of 0.2 fM. The biosensor has showed an appreciated sensitivity to PCR samples of genomic DNA from Mycobacterium tuberculosis, and has been able to detect a single mutation which confers resistance of M. tuberculosis to rifampicin drug. [Display omitted] •Synthesis of new redox polymer modified with ferrocene groups and carboxylic acids as functional groups in side chains.•The functional groups give the flexibility for direct covalent attachment of biomolecules.•The redox indicator was used for monitoring the electrochemical behavior of DNA detection.•Biosensor has showed a good sensitivity to DNA probe of Hepatitis C and PCR samples of DNA from Mycobacterium tuberculosis.