Enzyme free highly sensitive glucose biosensor based on Ag/Cu₂O nanostructures deposited on TiO₂ nanotube arrays

A highly sensitive non-enzymatic biosensor based on a deposition of silver nanoparticles with Cu₂O on TiO₂ nanotube arrays has been developed for the detection of glucose. The TiO₂ nanotubes (TNTs) were fabricated by anodization on a thin plate Ti6Al4V titanium alloy. Subsequently, Cu₂O was deposited on the TNTs using the wet chemical bath deposition method, followed by the electro-deposition of Ag nanomaterials. The crystal structure, phases, and morphology of the nanostructure (Ag-Cu₂O@TiO₂) were examined using energy-dispersive X-ray, transmission electron microscopy, and field emission scanning electron microscopy. The addition of Cu₂O and Ag to TNTs enhances the electroactive surface area, which results in a faster rate of electron transfer. The electrochemical behavior of Ag-Cu₂O@TiO₂ was investigated using cyclic voltammetry, electrochemical impedance spectroscopy, and amperometry techniques. The Ag-Cu₂O@TiO₂ exhibited a high level of sensitivity (1010.20 μA mM⁻¹ cm⁻²), low detection limit of 36 µM, and a rapid response time (2 s). Furthermore, the real-time analysis of glucose in human blood serum demonstrated a high level of accuracy. This work illustrates the deposition of Ag-Cu₂O on TNTs for fabrication of excellent selectivity, reproducibility, and remarkable stability.