The Development of Non-Enzymatic Glucose Biosensors Based on Electrochemically Prepared Polypyrrole–Chitosan–Titanium Dioxide Nanocomposite Films

The performance of a modified electrode of nanocomposite films consisting of polypyrrole-chitosan-titanium dioxide (Ppy-CS-TiO2) has been explored for the developing a non-enzymatic glucose biosensors. The synergy effect of TiO2 nanoparticles (NPs) and conducting polymer on the current responses of the electrode resulted in greater sensitivity. The incorporation of TiO2 NPs in the nanocomposite films was confirmed by X-ray photoelectron spectroscopy (XPS) spectra. FE-SEM and HR-TEM provided more evidence for the presence of TiO2 in the Ppy-CS structure. Glucose biosensing properties were determined by amperommetry and cyclic voltammetry (CV). The interfacial properties of nanocomposite electrodes were studied by electrochemical impedance spectroscopy (EIS). The developed biosensors showed good sensitivity over a linear range of 1-14 mM with a detection limit of 614 M for glucose. The modified electrode with Ppy-CS nanocomposite also exhibited good selectivity and long-term stability with no interference effect. The Ppy-CS-TiO2 nanocomposites films presented high electron transfer kinetics. This work shows the role of nanomaterials in electrochemical biosensors and describes the process of their homogeneous distribution in composite films by a one-step electrochemical process, where all components are taken in a single solution in the electrochemical cell

One-step electrochemical deposition of Polypyrrole–Chitosan–Iron oxide nanocomposite films for non-enzymatic glucose biosensor

One-step electrodeposition method of Polypyrrole–Chitosan–Iron oxide (Ppy–CS–Fe3O4) nanocomposite films (Ppy–CS–Fe3O4NP/ITO) has been developed for the fabrication of advanced composite coatings for biosensors applications. The FESEM and EDX results provide the evidence of successful incorporation of Fe3O4 into Ppy–CS molecules. The presence of Fe3O4 nanoparticles in the nanocomposite films was further confirmed by the XRD and XPS spectrums. The fabricated electrode Ppy–CS–Fe3O4 NP/ITO shows a fast amperometric response with high selectivity to detect glucose non-enzymatically with improved linearity (1–16 mM) and the detection limit of (234 μM) at a signal-to-noise ratio (S/N=3.0)

A single-step synthesis of nitrogen-doped graphene sheets decorated with cobalt hydroxide nanoflakes for the determination of dopamine

Nitrogen-doped reduced graphene oxide (NrGO) sheets decorated with Co(OH)2 nanoflakes were prepared by a single-step hydrothermal process. The morphological and structural characterizations of as synthesized NrGO@Co(OH)2 nanoflakes were performed by field emission scanning electron microscopy (FESEM), EDX-mapping and X-ray diffraction (XRD). NrGO@Co(OH)2 nanoflakes modified glassy carbon electrode (GCE) was used for electrochemical sensing of dopamine in neutral medium. The nanocomposite modified electrode showed enhanced electrochemical sensing ability for the detection of dopamine and the limit of detection (LoD) was found to be 0.201 μM with a sensitivity value of 0.0286 ± 0.002 mA mM−1. Interference studies revealed that NrGO@Co(OH)2─GCE endow excellent selectivity for DA detection even in the presence of higher concentration of common co-existing physiological interfering analytes. Additionally, proposed sensor demonstrated excellent performance in urine samples with promising reproducibility and stability