E-DNA biosensors of M. tuberculosis based on nanostructured polypyrrole

Abstract

The objective of this paper is to demonstrate the potential of nanostructured polypyrrole formed by template free as platform for amperometric detection of DNA. The nanowires of polypyrrole (nw-PPy) are formed through electrochemical polymerization and chemically modified by electrochemical oxidation of ethylene diamine or dendrimers PAMAM to obtain aminated surface. The DNA probe and ferrocenyl group, as redox reporter, were covalently linked to the surface of nw-PPy. The chemical structure of nanostructured platform was characterized through SEM, FT-IR and XPS and the electrochemical properties through cyclic voltammetry and electrochemical impedance spectroscopy (EIS). We show that the properties of nw-PPy such as, hydrophilic character and large surface area have large effect on the electronic properties. Thus, the electrochemical performance is increased compared to others nanomaterials considering the obtained value of the rate of electron transfer of 18 s -1 . These properties allow enhanced DNA sensing where detection limit of 0.36 atomolar without any amplification step. The biosensor can be applied in detection of genomic DNA of Mycobacterium tuberculosis and the mutated one which present the resistance to rifampicin and large selectivity was demonstrated. We believe that nw-PPy modified with redox marker is a promising platform for electrochemical biosensors and can be applied for various diagnosis prospects.

Polypyrrole Nanomaterials: Structure, Preparation and Application

“…PPy nanomaterials have been used in the fabrication of various biosensors due to their unique properties [ 192 , 193 ]. Biosensors mainly detect proteins [ 194 , 195 , 196 ], hormones [ 197 , 198 ], DNA [ 199 , 200 , 201 ], RNA [ 202 , 203 ], Cu 2+ [ 204 , 205 ] and others [ 206 , 207 , 208 , 209 , 210 ].…”

“…PPy nanomaterials modified with redox markers are a promising platform for electrochemical biosensors, which can be applied to various diagnostic prospects. Without using any templates, Khoder et al [ 201 ] prepared PPy NWs using simple electropolymerization. Without any amplification operations, the detection limit of the PPy NWs modified E-DNA biosensor with ferrocene as the redox marker is 0.36 aM.…”

Recent Advances of Conducting Polymers and Their Composites for Electrochemical Biosensing Applications

“…Ferrocene and its derivatives are very popular redox mediators used in biosensor construction. They are very stable in both oxidized and reduced form, have excellent redox reversibility, and their redox capacity is not affected by the pH of the solution [110,140]. A highly sensitive reagentless glucose detection electrode is designed with copolymerization of ferrocene and functionalized PPY.…”

“…The functionalization with the mediator shifts the working potential from 0.6 V to 0.4 V and prevents mediator leaching, thus increasing stability and limiting the interference in real samples. A biosensor surface is modified with ferrocene and PPY for bacterial detection with a LOD of 100 fM [140]. A sensitive microfluidic set-up coupled with a modified SPE is designed for neurotransmitter detection and able to detect the target analyte as low as 34 pM [100].…”

Frozen‐State Polymerization as a Tool in Conductivity Enhancement of Polypyrrole

“…Polypyrrole (PPy) has gathered compelling attention among conducting polymers due to its facile preparation and unique physico-chemical properties. [1,2] As a result of its relatively high conductivity, environmental stability, and biocompatibility, PPy has been used in many applications, for example, bio and gas sensors, [3,4] micro-actuators, [5] battery electrodes, [6,7] supercapacitors [8,9] and adsorption. [10] The insolubility and infusibility of PPy have restricted its practical applications; however, its processability and more importantly, conductivity can be improved by the formation of nanostructures.…”