A Sensitive and Selective Non-Enzymatic Dopamine Sensor Based on Nanostructured Co3O4–Fe2O3 Heterojunctions

• Published in: Chemosensors Vol. 11; no. 7; p. 379
• Main Authors: Khan, Madiha, Abid, Khouloud, Ferlazzo, Angelo, Bressi, Viviana, Espro, Claudia, Hussain, Mozaffar, Foti, Antonino, Gucciardi, Pietro Giuseppe, Neri, Giovanni
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.07.2023
• Subjects: Adsorption; Alzheimer's disease; Biosensors; Carbon; Cobalt oxides; Dopamine; dopamine electrochemical detection; Electrochemical analysis; Electrodes; Enzymes; Ferric oxide; Heterojunctions; Heterostructures; metal oxide; Metal oxides; Morphology; Nanocomposites; Nanoparticles; P-n junctions; Ratios; Scanning electron microscopy; Sensors; Sol-gel processes; Spectrum analysis; Surface area; Synthesis
• ISSN: 2227-9040; 2227-9040
• DOI: 10.3390/chemosensors11070379

In the present work, a study was carried out with the aim of enhancing the performance of electrochemical biosensors based on Co3O4:Fe2O3 heterojunctions. Specifically, the redox behavior of screen–printed carbon electrodes (SPCEs) modified with Co3O4:Fe2O3 (0.5 wt%:x wt%) nanocomposites, where x ranged from 0.1 to 0.5 wt%, was examined in detail. The hybrid nanocomposites were synthesized using the sol-gel auto-combustion method. Several characterization methods were performed to investigate the morphology, microstructure, and surface area of the pure Co3O4, pure Fe2O3, and the synthesized Co3O4:Fe2O3 nanocomposites. Using cyclic voltammetry (CV) tests, the electrochemical behavior of the modified electrodes toward the dopamine (DA) molecules was investigated. The modified Co3O4:Fe2O3, (0.5 wt%, x = 0.4 wt%)/SPCE resulted in a sensor with the best electrochemical performance toward DA. A high linear relationship between DA concentrations and the faradic current variation (ipa (μA) = 0.0736 + 0.1031 CDA (μA) and R2 = 0.99) was found in the range of 10–100 μM. The sensitivity value was computed to be 0.604 µA µM−1cm−2 and the limit of detection (LOD) 0.24 µM. Based on the characterization and electrochemical results, it can be suggested that the formation of Co3O4:Fe2O3 heterostructures provides a large specific surface area, an increased number of electroactive sites at the metal oxide interface and a p–n heterojunction, thus ensuring a remarkable enhancement in the electrochemical response towards DA.