An amperometric glucose biosensor based on a GOx-entrapped TiO2–SWCNT composite

Single-walled carbon nanotubes (SWCNT) were deposited onto indium tin oxide (ITO)-coated glass using an arc-discharge method. Titanium oxide (TiO2) was coated onto the SWCNTs using a metal–organic chemical vapor deposition (MOCVD) technique. The surface morphology and crystal structure of a TiO2–SWCNT nanowire structured composite was investigated using FESEM, XRD and Raman spectra. The TiO2–SWCNT composite film was used to immobilize glucose oxidase (GOx). The immobilization of GOx onto TiO2–SWCNT composite film was characterized by FTIR spectroscopy. The glucose-sensing properties of a GOx/TiO2–SWCNT/ITO electrode was studied at −0.25 V, and it showed a linear range of detection from 10 μM to 1.40 mM in a response time of 9 s with a low detection limit of 10 μM and a sensitivity of 5.32 μA mM−1 cm−2. The Michaelis–Menten constant was 0.83 mM. The effects of interfering species like uric acid, ascorbic acid and sucrose were also studied.