Abstract
In this study, we used the concept of overnight hydrolysis of polyvinyl amine to grow cobalt oxide (Co3O4) nanostructures with enhanced catalytic properties. The controlled synthesis of Co3O4 nanostructures was carried out with the hydrothermal method using hydrolyzed products. Results showed that the hydrocarbon chain and amide groups produced during the growth process have a great impact on both the morphology and catalytic properties of Co3O4 nanostructures. In fact, the hydrolyzed products supported the growth of nanostructures with a well-defined almost one-dimensional (1-D) morphology of Co3O4 nanowires with a high surface/volume ratio. The as-prepared nanowires were loaded with a high amount of glucose oxidase in order to make them sensitive to glucose and observe a potentiometric response in its presence. The performance of the fabricated biosensor was evaluated in terms of different analytical parameters such as linear range, stability, reproducibility, repeatability, life time, selectivity, and response time. Thus, the obtained Co3O4-based glucose biosensor exhibited a linear response over the concentration range from 0.0005 to 6 mM, with a limit of detection of 0.0001 mM. The estimated Nernstian slope for the glucose biosensor was 42 mV/dec, with stability that exceeds four weeks. Using electrochemical impedance spectroscopy, the Co3O4 nanowires showed a low charge transfer resistance of 2.2 x 10(3) Ohms. Practically, the biosensor was used successfully to measure the glucose concentration in real blood samples. The results obtained confirm that the proposed glucose biosensor can be used as an alternative tool for monitoring glucose levels. The synthesis procedure described herein has a high potential to produce nanostructured materials on a large scale with well-defined morphology and improved catalytic properties for possible applications in batteries, supercapacitors, and water splitting.