Electrochemical DNA hybridization sensors based on conducting polymers

Abstract

Conducting polymers (CPs) are a group of polymeric materials that have attracted considerable attention because of their unique electronic, chemical, and biochemical properties. This is reflected in their use in a wide range of potential applications, including light-emitting diodes, anti-static coating, electrochromic materials, solar cells, chemical sensors, biosensors, and drug-release systems. Electrochemical DNA sensors based on CPs can be used in numerous areas related to human health. This review summarizes the recent progress made in the development and use of CP-based electrochemical DNA hybridization sensors. We discuss the distinct properties of CPs with respect to their use in the immobilization of probe DNA on electrode surfaces, and we describe the immobilization techniques used for developing DNA hybridization sensors together with the various transduction methods employed. In the concluding part of this review, we present some of the challenges faced in the use of CP-based DNA hybridization sensors, as well as a future perspective.

Figure 1.

Schematic representation of a general electrochemical DNA sensor based on conducting polymers.

Figure 2.

Schematic illustration of DNA probe immobilization through avidin-biotin chemistry and the hybridization of target DNA on a self-assembled monolayer (SAM)-modified Au electrode. (Reproduced with permission from [99]. Copyright 2014, American Chemical Society.)

Figure 3.

Schematic representation of the immobilization of probe DNA and the hybridization of a target sequence (I), and plots of (A) impedance and (B) admittance before and after hybridization in a phosphate buffer solution (II). (Redrawn and reproduced with permission from [146]. Copyright 2014, American Chemical Society.)

Figure 4.

Schematic illustration of the poly-5,2′:5′,2″-terthiophene-3′-carboxylic acid (pTTCA)/ dendrimer (DEN)/ Au nanoparticles (AuNP)/biomolecule-linked avidin-hydrazine assembly developed for (A) DNA and (B) protein sensors, based on the electrocatalytic activity of hydrazine. (Reproduced with permission from [154]. Copyright 2014, American Chemical Society.)

Figure 5.

NH₂-DNA and peptide nucleic acid (PNA) immobilization on polyaniline-coated gold film. (Redrawn with permission from [174]. Copyright 2014, American Chemical Society.)

Figure 6.

(1) Immobilization of the peptide nucleic acid (PNA) probe; and (2) hybridization of the target DNA onto poly(JUG-co-JUGA)-modified glassy carbon electrode (GCE) together with the corresponding square wave voltammetry (SWV) signals for (1) PNA probe immobilization, and (2) target DNA hybridization. (Reproduced with permission from [182]. Copyright 2014, Elsevier.)

Figure 7.

Schematic representation of the preparation of an electrochemical DNA sensor based on a poly(indole-5-carboxylic acid) (PICA) conducting polymer. (Redrawn from [187]. Copyright 2014, Elsevier.)