A Nonoxidative Sensor Based on a Self-Doped Polyaniline/Carbon Nanotube Composite for Sensitive and Selective Detection of the Neurotransmitter Dopamine

Abstract

Most of the current techniques for detection of dopamine exploit its ease of oxidation. However, the oxidative approaches suffer from a common problem. The products of dopamine oxidation can react with ascorbic acid present in samples and regenerate dopamine again, which severely limits the accuracy of detection. In this paper, we report a nonoxidative approach to electrochemically detect dopamine with high sensitivity and selectivity. This approach takes advantage of the high performance of our newly developed poly(anilineboronic acid)/carbon nanotube composite and the excellent permselectivity of the ion-exchange polymer Nafion. The binding of dopamine to the boronic acid groups of the polymer with large affinity affects the electrochemical properties of the polyaniline backbone, which act as the transduction mechanism of this nonoxidative dopamine sensor. The unique reduction capability and high conductivity of single-stranded DNA functionalized, single-walled carbon nanotubes greatly improved the electrochemical activity of the polymer in physiological buffer, and the large surface area of the carbon nanotubes largely increased the density of the boronic acid receptors. The high sensitivity along with the improved selectivity of this sensing approach is a significant step forward toward molecular diagnosis of Parkinson's disease.

Increased response/recovery lifetimes and reinforcement of polyaniline nanofiber films using carbon nanotubes

“…CNTs have previously been combined with both bulk and nano PAni to improve its properties for a range of applications, including actuation and sensing [4,6,[30][31][32][33][34][35][36][37][38][39][40]. For example, Spinks et al report using CNTs to improve the tensile strength and stress loading of PAni for artificial muscles [6].…”

Selective Detection of Dopamine Using Glassy Carbon Electrode Modified by a Combined Electropolymerized Permselective Film of Polytyramine and Polypyrrole‐1‐propionic Acid

“…Insufficient DA level caused by the degeneration of dopaminergic neurons in the nigrostriatal pathway is related with neurological diseases such as Parkinsonism, schizophrenia and Huntington, leading to motor dysfunction [4 -7]. Therefore, sensitive and selective determination of DA in vitro and in vivo could be useful for the diagnostics of such diseases and the evaluation of drug efficacy [7].…”

Molecularly imprinted silica films prepared by electroassisted deposition for the selective detection of dopamine

“…Therefore the concentration ratio for DA:AA in blood plasma is around 1:10000 or lower. [29,30] In order to improve the selectivity of the electrodes for this application big efforts have been made to modify the electrode surfaces by different strategies, including graphene, nanoparticles, conducting polymers, self-assembled monolayers, etc. [31][32][33][34]These modified electrodes obtained good selectivity for ranges of DA:AA concentration ratio of 1:1000 in the best case.…”