Non-enzymatic amperometric glucose biosensor from zinc oxide nanoparticles decorated multi-walled carbon nanotubes

The present work describes the development of novel ZnO dispersed multi-walled carbon nanotubes (MWNT) based non-enzymatic glucose biosensor with 1 M NaOH solution as the supporting electrolyte. For a comparison, the same material has been used for the fabrication of enzymatic biosensor and studied its electrochemical activity with phosphate buffer solution as the electrolyte. MWNT have been synthesized by catalytic chemical vapor decomposition (CCVD) and a simple sol-gel method was used for decorating crystalline ZnO nanoparticles on MWNT. Cyclic voltammetry and chronoamperometry were used to study and optimize the electrochemical performance of the resulting enzymatic and non-enzymatic ZnO/MWNT biosensors. The non enzymatic Nafion/ZnO/MWNT/GC electrode shows linearity in the range 700 nM to 31 mM with the detection limit of 500 nM. Similarly enzymatic biosensor fabricated using Nafion/GOD/ZnO/MWNT on glassy carbon electrode (GCE) shows a linearity from 1 microM to 22 mM. This excellent performance of non enzymatic Nafion/ZnO/MWNT/GC is due to high surface area, good electron transfer rate of ZnO/MWNT and the high electrochemical catalytic activity of ZnO in NaOH solution.