Electrochemically Effective Surface Area of a Polyaniline Nanowire-Based Platinum Microelectrode and Development of an Electrochemical DNA Sensor

Abstract

Electrochemical DNA sensors based on nanocomposite materials of polyaniline nanowires (PANi NWs) have been published in the literature. However, it is interesting that there are very few research studies related to the development of electrochemical DNA sensors based on PANi NWs individually. In this study, PANi NWs were synthesized site-specifically on a Pt microelectrode with only 0.785 mm2 area using an electropolymerization procedure. The electrosynthesis allows direct deposition of PANi NWs onto the Pt microelectrode in a rapid and cost-effective way. The good properties of PANi NWs including uniform size, uniform distribution throughout the Pt working electrode, and H2SO4 doping which improved the conductivity of the PANi material were obtained. Especially, the electrochemically effective surface area of the PANi NW-based Pt microelectrode determined in this work is nearly 19 times larger than that of the Pt working electrode. The PANi NW layer with large electrochemically effective surface area and high biocompatibility is consistent with the application in electrochemical DNA sensors. The fabricated DNA sensors show advantages such as simple fabrication, direct detection, high sensitivity (with the detection limit of 2.48 × 10−14 M), good specificity, and low sample volume requirement. This study also contributes to confirm the role of PANi NWs in DNA probe immobilization as well as in electrochemical signal transmission in the development of electrochemical DNA sensors.

Voltammetric Sensor for Doxorubicin Determination Based on Self-Assembled DNA-Polyphenothiazine Composite

“…If the maximal potential was chosen below this value, no significant changes were observed on multiple cycling. Similar activation of the polymerization at high anodic potential was reported for the electropolymerization of aniline and phenothiazine dyes [47,56]. Increasing the number of the cycles of the potential between −0.5 and 1.3 V consecutively increased the peaks attributed to the products of electrosynthesis (0.4 V on anodic branch of the voltammogram and 0.2 V at the cathodic branch).…”

“…Recently, we have studied the electrochemical behavior of N-phenyl-3-(phenylimino)-3H-phenothiazin-7-amine (PhTz) with electropolymerization, alone and in the assembly of the DNA sensor [ 53 ]. Phenyl imine fragments present in its structure allow two mechanisms of polymerization, including the one proposed for polyaniline in strong acidic media [ 54 , 55 , 56 ] and another one attributed to the phenothiazine core. In this work, we have for the first time polymerized the PhTz from the acidic media and showed intrinsic redox activity of the product (polyPhTz) in the assembly of the DNA sensor and in the presence of doxorubicin as a model intercalator.…”

MIL‐53(Fe)/rGO: A new material applied in an electrochemical sensor for detection of Cd(II) ions in aqueous solutions

“…Recently, studies focusing on electrochemical sensors have increased significantly because of many advantages including high sensitivity, easy fabrication, simple operation, manifesting quick results. [ 8‐11 ] Specially, the ability to simultaneously detect heavy metal ions of this method shows its great application potential in practice. [ 12‐15 ]…”

“…Recently, studies focusing on electrochemical sensors have increased significantly because of many advantages including high sensitivity, easy fabrication, simple operation, manifesting quick results. [8][9][10][11] Specially, the ability to simultaneously detect heavy metal ions of this method shows its great application potential in practice. [12][13][14][15] Metal-organic frameworks (MOFs) are materials with a cyclic structure made up of metal ion nodes (clusters) connected to each other via organic ligands.…”