Highly Sensitive Enzyme‐free Sensor Based on a Carbon Paste Electrode Modified with Binary Zinc Oxide/Polyaniline Nanocomposites for Dopamine, Ascorbic Acid and Uric Acid Sensing

Abstract

Hybrid composites ZnO/PANI were facily synthesized by a sonication process at room temperature. This procedure is non-expensive, time/energy saving and environmentally safe. The as-prepared ZnO/PANI were characterized by FTIR, UV-vis spectroscopies and SEM in order to investigate the structure and morphology of the studied composites. The samples were used to modify carbon paste electrode (CPE) in order to develop electrochemical biosensors (ZnO/PANI/CPE). The sensing properties of the nanoparticles were evaluated for dopamine, ascorbic acid and uric acid non-enzymatic detection. The effect of percentage of polyaniline in the composites and the effect of calcination on the biosensor's response were also examined in the present study. It was revealed that the existence of PANI in ZnO/PANI/CPE largely enhanced the electroactive surface area and therefore the sensitivity for electrochemical sensing. A good electrochemical behavior was noted for ZnO/40 wt% PANI-cal/ CPE modified electrode toward DA, AA and UA oxidation. The electroactive surface area of the previously mentioned modified electrode (0.235 cm 2 ) was two times higher than that of the bare electrode (0.117 cm 2 ). The liner relationships between current intensities and concentrations were found to be 0.01-1.4 mM, 0.1-1.3 mM and 0.01-0.12 mM, with detection limit of 0.029 mM, 0.063 mM and 0.007 mM, for DA, AA and UA respectively. In the mixtures of ascorbic acid (AA), dopamine (DA) uric acid (UA) and glucose (Glu) the sensor showed high selectivity of DA with low interference of ascorbic acid by a current change of 14 %. The asprepared ZnO/PANI/CPE biosensor displayed a good reproducibility and stability.

Self-Standing 3D-Printed PEGDA–PANIs Electroconductive Hydrogel Composites for pH Monitoring

“…All these outcomes suggest that the resistive interface phenomena are greater for PEGDA-PANIs than PEGDA-PANI. However, it is fundamental to note that the absolute impedance values at 1 Hz are lower than 8 kΩ for both the investigated ECHs, as well as that these values are in line with those recorded for other PANI-based composites commonly proposed as electrode materials for sensing applications [52][53][54][55][56][57].…”

“…Recent studies have already focused on PANI-based composites for sensing applications [52][53][54][55][56][57]. However, the activity of the polymer phase was generally supported by the presence of nanoparticles [53,54,56] or metal or carbon electrodes [52,57]. The novelty of the present research relies on the production of a fully 3D-printed polymeric-active material with pH-responsive properties tunable in the 2-7 pH range.…”

“…Recent studies have already focused on PANI-based composites for sensing applications [52][53][54][55][56][57]. However, the activity of the polymer phase was generally supported by the presence of nanoparticles [53,54,56] or metal or carbon electrodes [52,57].…”

Common Transition Metal Oxide Nanomaterials in Electrochemical Sensors for the Diagnosis of Monoamine Neurotransmitter‐Related Disorders

“…For instance, the electroactive surface area of PANI/ZnO modified carbon paste electrode was reported to be 75 % higher than that of the ZnO NP-modified carbon paste electrode. [136] This outcome suggests that the inclusion of metal oxide NPs in various composites improved the electroactive surface area of the composite, among other changes.…”

“…The determination of the electroactive surface area of the metal oxide NPs and their corresponding composites with cyclic voltammetry data recorded in the redox probe or monoamine neurotransmitters solution shows that the electroactive surface area of the composites is higher than those of the nanomaterials that make up the composite. For instance, the electroactive surface area of PANI/ZnO modified carbon paste electrode was reported to be 75 % higher than that of the ZnO NP‐modified carbon paste electrode [136] . This outcome suggests that the inclusion of metal oxide NPs in various composites improved the electroactive surface area of the composite, among other changes.…”