Synthesis and characterization of a novel non-enzymatic glucose biosensor based on polyaniline/zinc oxide/multi-walled carbon nanotube ternary nanocomposite

Novel polyaniline/zinc oxide/multi-walled carbon nanotube (PANI/ZnO/MWCNT) ternary nanocomposite was fabricated as a non-enzymatic glucose biosensor. Thermal chemical vapor deposition (CVD) process was employed to synthesize vertically aligned MWCNTs on stainless steel substrates coated by Co catalyst nanoparticles. In order to fabricate sensitive and reliable MWCNT-based biosensors, nanotubes density and alignment were adjusted by varying the CVD reaction time and cobalt sulfate concentration. The fabricated nanotubes were modified by ZnO particles through the potentiostatic electrodeposition technique. Optimal electrodeposition potential, electrodeposition time, and electrolyte concentration values were determined. The optimized ZnO/MWCNT nanocomposite was reinforced by polyaniline (PANT) nanofibers through the potential cycling technique, and the morphology, elemental composition, and phase structure of the fabricated nanocomposites were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD), respectively. The sensing mechanism of the PANI/ZnO/MWCNT electrode for the electrochemical detection of glucose was investigated, and the limit of detection and sensitivity values of the designed sensor were determined. The fast response time of the ternary nanocomposite-based sensor as well as its satisfactory stability and reproducibility, makes it a promising candidate for non-enzymatic detection of glucose in biomedical, environmental, and industrial applications.