Effect of electrical conditions on an impedimetric immunosensor based on a modified conducting polypyrrole

Abstract

This work has explored the development of impedimetric immunosensors based on a conducting copolypyrrole film to which a histidine tag antibody has been bound using a complex NTA chelator coordinated with copper as metal. The electrical properties of the copolymer film have been characterized by Electrochemical Impedance Spectroscopy (EIS). The experimental study of EIS was performed over a range of dc voltages from 0 to -1.4 V (vs saturated calomel electrode SCE) where the polypyrrole layers transit from their conducting to insulating state and to demonstrate the contribution of the copper complex as redox probe. The electrical behavior of the biomaterial at these various potentials was studied according to an equivalent circuit fitting the experimental parameters. The results indicated that better immunosensor characteristics were obtained at an applied potential of -1400 mV where the reduction of copper occurs. The impedance obtained at this potential shows a linear variation of charge transfer resistance (R ct ) with the specific antigen concentration in the range of 0.1 ng mL -1 to 10 ng mL -1 with a detection limit of 0.1 ng mL -1 . Moreover, this study demonstrates that these immunosensors exhibit high sensitivity, stability and reproducibility.

Physical and chemical characterization of adsorbed protein onto gold electrode functionalized with Tunisian coral and nacre

“…All measurements were performed at room temperature in PBS, pH 7. The electrochemical impedance (Z) can be represented as a sum of the real (Z re ) and imaginary (Z im ) components (Z = Z re + jZ im , where j = √−1) that originate generally from the resistance and capacitance of an electrolytic cell, respectively [31,32].…”

Bulk synthesis, optimization, and characterization of highly dispersible polypyrrole nanoparticles toward protein separation using nanocomposite membranes

“…Polypyrrole (PPy) is the one of most investigated conducting polymers, owing to its facile synthesis, good conductivity, redox properties, long-term environmental stability and biocompatibility as polymer in vivo [9], and has shown promising applications including sensors [10], actuators [11], photovoltaic/solar cells [12,13], electromagnetic interference shielding [14], and corrosion protection [15]. In addition, PPy nanocomposites have been shown biodegradability and biocompatibility, which are potentially useful in drug delivery and tissue engineering [5,16].…”

Electronic tongue for simultaneous detection of endotoxins and other contaminants of microbiological origin

“…Recently, other research groups have used electroactive polymers in impedance based immunosensors (Hafaida et al, 2010;Giroud et al, 2009). In these works the impedance spectra correspond to the typical behavior observed for electroactive films, proposing an equivalent circuit as the one depicted in Fig.…”